The lookup link for your HR Rep is found at the top right of this page: http://www.house.gov/
The lookup link for your (2) Senators is found at the top right of this page: http://www.senate.gov
Your Senators and House Rep will have "Contact" links on their respective homepages.
Once they are in office, they are totally unresponsive to constituents. Offer half a million bucks or more to their “campaign fund”, and they will return your call.
I contact mine frequently by phone and email. My rep (a good man, former county sheriff) after a few terms has decided not to run for re-election. Probably got sick of it. My senators, well....one is Bill Nelson who is lockstep with Obama, and the other is Rubio who is a little too pre-occupied right now to do his job he was actually elected to do.