(Cross-posted at Ponies & Pachyderms)
On November 7, 2006, 33 seats in the United States Senate will be up for grabs as those Senators last elected in 2000 are up for re-election.
At this point, the United States Senate is composed of 55 Republicans, 44 Democrats, and 1 Independent. Out of the 33 contested seats, 17 are Republican, 14 are Democrat, and 1 is an Independent (former Republican Seantor Jim Jeffords of Vermont).
To continue to hold the majority, the Republicans need to win 50 seats. For the Democrats to attain a majority, they need to win 7 (7 Republican, or 6 Republican and the 1 Independent).
According to the United States Senate 2006 Elections entry on wikipedia:
The market-based outcomes of an independent public trading exchange suggests as of June 7, 2006, that the most vulnerable Republican seats are Pennsylvania, Montana, and Ohio, respectively and are likely to switch control. In addition, the same market suggests that in Rhode Island and Missouri, the chance that the Republicans will keep the seat is less than two out of three. For the Democrats, two seats (Minnesota and New Jersey) fall below the two-out-of-three threshold of safety, but are still deemed likely by the public market to be retained by the Democrats.
The entry also notes that a number of Senators will be retiring – including Minnesota Senator Mark Dayton (D), Tennessee Senator Bill Frist (R), Vermont Senator Jim Jeffords (I), and Maryland Senator Paul Sarbanes (D).
Noteable incumbents planning on running for re-election include Senators Maria Cantwell (D-Washington), Joe Lieberman (D-Connecticut), Robert Menendez (D-New Jersey), Bill Nelson (D-Florida), Debbie Stabenow (D-Michigan), George Allen (R-Virginia), Conrad Burns (R-Montana), Lincoln Chafee (R-Rhode Island), Mike DeWine (R-Ohio), John Ensign (R-Nevada), Jon Kyl (R-Arizona), Rick Santorum (R-Pennsylvania), and Jim Talent (R-Missouri).