Aside from contacting your representative and tweeting at #dearjohn here are some quick and easy things you can do to oppose H.R.3 and H.R.358:
Sign the We Won’t Go Back to the Back Alley petition at MoveOn.org
Modify and send this form letter from Naral to your representative.
Sign the Redefining Rape petition at Moveon.org
Also related things you can do to protect reproductive rights:
Tell Congress you want Birth Control to be free under the new healthcare law
If I’ve forgotten anything, and I’m sure I have, feel free to link in the comments!