class - Article I, section 3 of the Constitution requires the Senate to be divided into three classes for purposes of elections. Senators are elected to six-year terms, and every two years the members of one class—approximately one-third of the Senators—face election or reelection. Terms for Senators in Class I expire in 2013, Class II in 2015, and Class III in 2011.

When you go here. Look to the Right and Look at their Class.
http://www.senate.gov/general/contact_i ... rs_cfm.cfm

Class III - Senators Whose Terms of Service Expire in 2011

Class III terms run from the beginning of the 109th Congress on January 3, 2005, to the end of the 111th Congress on January 3, 2011. Senators in Class III were elected to office in the November 2004 general election, unless they took their seat through appointment or special election.


Bayh, Evan (D-IN)
Bennet, Michael F. (D-CO)
Boxer, Barbara (D-CA)
Burris, Roland W. (D-IL)
Dodd, Christopher J. (D-CT)
Dorgan, Byron L. (D-ND)
Feingold, Russell D. (D-WI)
Inouye, Daniel K. (D-HI)
Leahy, Patrick J. (D-VT)
Lincoln, Blanche L. (D-AR)
Mikulski, Barbara A. (D-MD)
Murray, Patty (D-WA)
Reid, Harry (D-NV)
Schumer, Charles E. (D-NY)
Specter, Arlen (D-PA)
Wyden, Ron (D-OR)

Bennett, Robert F. (R-UT)
Bond, Christopher S. (R-MO)
Brownback, Sam (R-KS)
Bunning, Jim (R-KY)
Burr, Richard (R-NC)
Coburn, Tom (R-OK)
Crapo, Mike (R-ID)
DeMint, Jim (R-SC)
Grassley, Chuck (R-IA)
Gregg, Judd (R-NH)
Isakson, Johnny (R-GA)
LeMieux, George S. (R-FL)
McCain, John (R-AZ)
Murkowski, Lisa (R-AK)
Shelby, Richard C. (R-AL)
Thune, John (R-SD)
Vitter, David (R-LA)
Voinovich, George V. (R-OH)

http://www.senate.gov/pagelayout/refere ... ss_III.htm