Which vote or promise is important to you?
Special Unicorn, check this out:
http://www.senate.gov/legislative/LIS/roll_call_lists/roll_call_vote_cfm.cfm?congress=110&session=1&vote =00235
http://www.campaignforliberty.com/kb.php
http://www.numbersusa.com/content/
http://www.opencongress.org/

It's good do have third party and independent candidates to vote for.
http://www.politics1.com/p2008.htm
http://www.numbersusa.com/content/elections.html
Another site with past votes and times they voted:
http://projects.washingtonpost.com/congress/?nid=roll_housesenvote

Most missed votes:

http://projects.washingtonpost.com/congress/110/senate/vote-missers/

Their income:
http://projects.washingtonpost.com/congress/disclosure-reports/2007/house/
Senate Incomes:
http://projects.washingtonpost.com/congress/disclosure-reports/2007/senate/