Source:
Washington Post... Byrd, at 90 the longest-serving senator in history, has been ill for much of the past year. That has sparked behind-the-scenes intrigue over his chairmanship of a committee that controls about $1 trillion in annual federal spending.
Those discussions flared again last week as public debate on the war funding vote neared, according to aides and senators who would discuss them only on the condition of anonymity. At a leadership meeting of about 15 Senate Democrats, they said, the talk of replacing Byrd came up as the senators realized the bill needs to be addressed, most likely in a public hearing next week....
...The Capitol Hill newspaper Roll Call has reported that an effort is underway to oust Byrd, while the Hill has suggested that Sen. Patrick J. Leahy (D-Vt.) has privately thrown himself into the mix to replace the ailing chairman. That would breach senatorial tradition because it would require leapfrogging a more senior colleague on the committee, Sen. Daniel K. Inouye (D-Hawaii).
Byrd has responded with phone calls to colleagues to reassure them that his health is improving...Byrd's office called the talk of his stepping down from the committee chairmanship "petty rumor-mongering" and said he will serve out the year....
Read more:
http://www.washingtonpost.com/wp-dyn/content/article/2008/04/15/AR2008041502793.html?sub=AR
The article speculates that Byrd may step down at the beginning of the new Congress, following the example of the late Strom Thurmond