http://www.gval.com has exemption info. for US states.

More vaccine info including support
groups:http://www.unc.edu/~aphillip/www/vaccine/resrcntr.htm

Freedom of choice vs. Mandatory Vaccinations: (San Diego CA)
http://www.access1.net/via/PROCHOICE/freedom.htm

Bottom line: You do NOT have to subject your child to any medical
treatment/procedure/etc. that you don't want to subject them to. Claim
religious exemption if you must ...though some states require proof.
You
could tell them that your religion is "NeanderZen" or "Falconry"...not
sure
how the state would react to that though! :D

If "herd immunity" were something real, unvaccinated children would
only
pose a "health threat" to themselves. My friend took her kid to the
ped for
some minor thing, and another kid in the waiting room had mumps. He
had been
given MMR "on schedule". The mother couldn't understand how that could
happen. Duh. Vaccines are not infallible!

(By the way, this reminds me that it's national pet peeve week!)