In the Senate they are pojecting 46 solid Democratic seats with 3 of the remaining 19 seats that are in play leaning Democratic. Thus, of the 8 toss up seats the Dems only have to win one to retain the majority. The Senate races in Penn, West Virginia, Illinois, Nevada and Washington are 5 of those 8 toss up seats and the Dems are very likely to win at least one or more of those seats.
http://elections.nytimes.com/2010/senateThe House things are much closer. Only 155 seats are solid Democratic versus 168 solid for the Republicans. But of the 112 seats that are in play 48 lean Democratic while only 27 are leaning to the GOP. That gives the Dems 203 solid & leaning seats and the GOP 195 solid & leaning seats. Of the remaining 37 that are still considered in play, the Dems only need to win 15 to retain the majority while the Republicans have to win 23. Since amost all of those seats currently have a Democratic incumbent and many are in deep blue states there is a good chance that the Dems will retain a slim majority.
http://elections.nytimes.com/2010/house