Reader Josh sent a link to the Immunization Safety Review Committee's 2004 Immunization Safety Review: Vaccines and Autism whose description reads in part:
This eighth and final report of the Immunization Safety Review Committee examines the hypothesis that vaccines, specifically the measles-mumps-rubella (MMR) vaccine and thimerosal-containing vaccines, are causally associated with autism. The committee reviewed the extant published and unpublished epidemiological studies regarding causality and studies of potential biologic mechanisms by which these immunizations might cause autism. Immunization Safety Review: Vaccines and Autism finds that the body of epidemiological evidence favors rejection of a causal relationship between thimerosal-containing vaccines and autism. The book further finds that potential biological mechanisms for vaccine-induced autism that have been generated to date are only theoretical.
The 214 page report is available for download as a .pdf for ~$35. And to be fair, I haven't been following this issue closely, so I don't know what's "right." I'm just interested in the issue, especially these days as more and more of my friends are starting families.