Most Senators and Congressmen have email forms that can be used to contact them. Although they probably don't read 99.9% of the letters they receive, you might get lucky. Plus, there is usually a place to input the subject of an email, and I'm willing to bet that they do keep track of how many letters they get about bills they vote on.
Here are my Senators and Representatives
Senator Jon Kyl
Senator John McCain
Representative Gabrielle Giffords (85719-2857 )
Representative Raúl M. Grijalva (85735-8803)