'Term Limits' Meehan (D) MA heads the list
http://arstechnica.com/news.ars/post/20060130-6079.html
The Lowell (MA) Sun first broke the story of congressional staffers who were making changes to Wikipedia entries from government computers with their boss' permission. An investigation into the entry for Representative Marty Meehan (D-MA) found that staffers in Meehan's office had replaced negative (but apparently accurate) references to Meehan's career with a positive, staff-written biography. The edits removed references to Meehan's (broken) promise not to run for office more than four times and to the size of his massive campaign war chest. Instead, they replaced such information with a positive statement about Meehan's "fiscally conservative voting record," among others.
All changes to Wikipedia are logged, so it was not a difficult matter to trace the source of the edits back to a House IP address
The following is a partial list of U.S. Senator biographies on the english-language Wikipedia edited by Senate employees.
Senator Conrad Burns' page was edited to remove negative comments as positive comments were added
Senator Norm Coleman's page was also edited to remove negative comments while positive comments were added
Senator Robert Byrd's page was vandalized
Senator Tom Harkin's criticism section was deleted, a major section on Israel & military removed and later vandalized by a different IP
Senator Joe Biden's page had a major edit removing significant criticism