LinksYour guide to money in the US elections
Contact Elected Officials - Links for all officials
Find Your House Representative
Find your Senators
About.com - How to write letters to congress - Great tips on writing the letter and where to send it
Excerpt from SlashDot
All this information is recorded somewhere on the House of Reps and Senate websites. I was scanning records hourly as S 1805 (Protection for Lawful firearms commerce) was being debated and voted on in the Senate. I'll dig up the links in a second — it'll be easier to spot once you've seen them before.
Oh, and CONGRESS.GOV can be used to search for the EXACT text of pending bills in both the Senate and House. They're a myriad of them though so you pretty much need to be involved with an activist group that will keep you posted on what bills are in committee and which ones have a chance of getting of committee. Unless your reps are on the actual committee it's not much use to call them up and voice opinions on a bill that's not going anywhere. Well, that's my take on it. Seems like your position would have more "oomph" if you call them when you know it's out of committee — shows that you're on top of the issue.
A good way to learn how all the voting works is to follow a specific organization. Here's an example:
American Family Association