Call 202-224-3121, which is the congressional switchboard, and from there they can direct your call to your member's office (Representative or Senators) by their name or your zip code; or search www.Congress.org for the direct number to a particular member’s office (useful for a mass call-in targeting the reps for your campus, to save donated cellphone minutes).
Before you call you can check out your Senators' and Representative's individual websites to see their position on issues and what committees they work on.
The staff answering the phones keep a tally of calls on different issues, for and against - if you call in the evening or weekend you can leave a voicemail. Below is a sample script of what you can say/ask of your members when you call, feel free to change or adapt it depending on your member of Congress.
Hello, I'm a constituent of Representative/Senator ________. I live in/I'm a student at ______. This week marks the 4th anniversary of our invasion of Iraq, 4 years of stealing young people's futures, and I'm calling in support of Books Not Bombs. I want to know what the Congressperson is doing to end the war NOW and re-fund education. I want to know where the member stands on these issues and what she/he is doing to act right now to immediately end the war and give all young people access to education.
[At this point they’ll thank you for calling and letting your member know what you think, with no definite stance]
I’d like to hear more from the Senator/Representative where she/he stands on this issue
[Then they’ll ask for your name (again) and address to send you a follow-up letter]
Congrats! Thanks for calling and putting the pressure on Congress to act!