Dennis at Balloon Juice regularly posts reminders to call your House and Senate reps and tell them to pass the healthcare bill. I've just called my Senator, and I'm going to call my Rep once I'm done reading my morning news feeds.
I know that calling important people can be kind of nerve-wracking, but just remember that these people are supposed to be working for you - even if you didn't vote for them, you can still decide whether or not to do so the next time they run. Also, the person who answers the phone is usually an intern - so while you should definitely be nice to them, don't be afraid to tell them how strongly you feel about this issue and how much you want your rep to vote for this bill.
If you need some easy steps to follow, Balloon Juice has a guide for first-time callers.