First, while the Serbian Bosnian did do massacres in Bosnia, the exact nature of what control (if any) Serbia had over those Serbs is questionable. Remember the Bosnian Serbs lived in Bosnia and have for Centuries. This wa the problem with Balkans BEFORE Yugoslavia was ever formed. Yugoslavia was formed after WWI as a combination of Slovens, Croats, Bosnian Muslims, Serbs and Albanians (With some Hungarians and Roma (Gypsies) through into the mix). The Non-Serbs complained the at the pre-WWII Government was to Serbian. Tito's compromise to settle the conflict was to federate Yugoslavia. Tito first did this by cutting back Serbia to the areas where they was few (if Any) non-Serbs. Tito them divided the rest of the Country between the various nationalities, all with significant Serbian Minorities (With the exception of Slovenia). The non-serbs were happy with this for it gave the Croats, Slovenes and Bosnian control over their own people, while the Serbs accepted it for their fellow Serbs outside Serbia were protected by the Federal Government.
This Social Compromise all fell apart once Bosnian and Croatia decided to leave Yugoslavia (The Slovenes also left but had very few Serbs within their borders). The problem was while the Bosnians and Croats from Bosnia and Croats wanted to leave Yugoslavia, the Serbs LIVING IN THOSE STATES DID NOT WANT TO. This was complicated by the fact the groups did NOT live side by side with each other in mixed communities, but lived in different regions of each state (With most Serbs living in area next to Serbia).
Thus what cause the War was NOT the Serbs revolting, but the Croats and Bosnians leaving Yugoslavia WITHOUT Addressing the concern of the the Serbs within their Countries (and this was reinforced by nationalists in Bosnia and Croatia that demanded the expulsion of the Serbs and other minorities from Croatia and Bosnia). Throughout the Bosnian problem NO ONE ADDRESSED the Concern of the Serbs except the Serbs themselves.
Now Technically Serbia stayed out of the War In Bosnia and Croatia (and Croatia technically did the same for Bosnia), but both Croatia and Serbia sent supplies to each side in the fight. Thus you had developed two states within Bosnia, the Bosnia Muslim State tied in with Catholic Croatia, and a Serbian State tied in with Serbia. Neither side recognizing each other which opened the way to the massacres by the Serbs to make their 1/3 of Bosnia almost 100% Serbian. At the end Serbia and Croatia in the Dayton Accords agreed to divide up Bosnia while technically keeping it one state. A lot less blood would have been lost had the Croats and Bosnians considered what the Serbs living in their States wanted. This was OPPOSED by Croatian Nationalist (Many of whom believe the Bosnian Muslims are just Croats of a different Religion as opposed to being a different Nationality).
This was complicated by the Serbs Living in Croatia. Just before the solution of the Problem of Bosnia these Serbs were DRIVEN OUT of their Homes by the Croats. Now you may think that was good, but these were Serbs who have lived in Croats for Centuries and were MILES away from the Conflict in Bosnia, they had NOTHING to do with Bosnia, but the Croats wanted them out of Croatia so they were driven out while World Attention was on Bosnia (The Expulsion of these Serbs may even have convinced the Serbs in Bosnia that they had gained as much land as they could and thus willing to sign a peace treaty).
Now, after the Bosnian situation as resolved, the Albanian in Kosovo revolted. Now Unlike Bosnia and Croatia, Kosovo had NOT been an independent state in the Yugoslavia Federation, but a self-governing region within Serbia. While the Kosovo Albanians were Sunni Moslems like the Bosnian Muslims, there was a Fundamental Difference between the Albanians and Bosnian Moslems. The main Difference is the Bosnian were Southern Slavs who had Converted to being Moslem while the Albanians are an ancient people who have lived in the Balkans since before the Roman Empire (and embraced Islam, because the Serbs were Orthodox). Remember while while there are other differences between the Croats, Serbs, and Bosnian Muslims. the main Difference is the Croats are Southern Slavs who are Catholic and have had Connection with Germany and the West for Centuries, the Serbs are Orthodox and connection was with Constantinople and Greece for Centuries and the Moslem Bosnians had been Christian Heretics in the Middle Ages who converted to Islam as the Turks expanded their empire into the Balkans.
The key is to remember the Serbs, Croats and Bosnian are all Southern Slavs who speak variation of each other languages, thus you have intercommunication between them. The Albanians speak a complexly different Language and who embraced Islam to justify their attacks on the Serbs (Before the Turkish Conquest the Albanians appears to have been Catholic, but directly tied to Rome NOT via Germany like the Croats and Slovenes). Thus the Albanians tend NOT to interact with the Serbs. Once the Bosnia War was over, Serbia decided to crack down on attacks on Serbian Holy Sites in Kosovo, this lead to further attacks on Serbs and Roma living in Kosovo (Yes the Serbs PROTECTED the Roma from attacks by the Albanian Natives of Kosovo). As this war increased in tempo, Clinton decided to tell Serbia to leave the Albanians Kosovans alone. When the President of Serbia REFUSED, the Air War Started. After a couple Months of Fighting the Serbs agreed to pull their troops out of Kosovo AS LONG AS THE US AGREED THAT Kosovo STAYED PART OF SERBIA. That is the Situation at the Present time. US peace keepers protecting Serbs and Roma from attacks by Kosovo Albanians, the Albanians ruling Kosovo, but Serbia saying Kosovo is still part of Serbia (A real mess).
As to Slobodan Milošević, what role, if any, he played in Bosnia is in Dispute, He claims he had little of no Control over the Serbs in Bosnia but just acted as their agent in Dayton. This is supported by people who knew him (While others said since he was President of Serbia he was responsible). When he lost office, the person he lost to attacked him FROM THE RIGHT as NOT having done enough to stop the "lost" of Kosovo and to support the Serbs in Bosnia.
Given the above, what happen in Yugoslavia in the 1990s happens to any country where the Social Compact of the Country is torn apart. People tend to revert to tribalism (More for protection then anything else). When the Serbs living outside Serbia Fears were NOT address the revolted to protect themselves. You can NOT expect to take people's rights away without a fight, unless you consider and give them a say in the movement. The Problem was The Croats did NOT want to give in to the Serbs living in Croatia and thus you ended up with Civil War. As to Kosovo, the Serbs believe they have an agreement with the US that Kosovo will stay part of Serbia. The Native Albanians can rule Kosovo but they MUST protect minorities rights (i.e. can NOT discriminate against Serbs and Roma who live in Kosovo). The Serbs fear that if Kosovo is made Independent of Serbia, the remaining Serbs and Roma will be driven out of Kosovo and the historical Serbia landmarks in Kosovo will be destroyed. This is UNACCEPTABLE to the Serbs in Serbia. If Kosovo wanted to be Independent the Government in Kosovo would address these concerns, but has refused. Thus the standoff and the present dispute and why Serbia is asking Russia to Veto any Independence of Kosovo.
http://en.wikipedia.org/wiki/Slobodan_Milo%C5%A1evi%C4%87