Although I'm an advocate for cosleeping, I don't think it's necessarily the right decision for every family, and I do think that those families choosing to cosleep need to do so safely. Now, I'm not saying that cosleeping is inherently dangerous, just that there are some guidelines to follow to make sure it's a safe option, just like there are guidelines to follow for safe sleeping in cribs. With that in mind, here are some links on cosleeping safety:
A list of links from Notre Dame's Mother-Baby Behavioral Sleep Laboratory.
A humorous look at cosleeping safety.
"Is sleeping with my baby safe? Can it reduce the risk of SIDS?" from James McKenna, Ph.D
Family Bed Safety from Mothering.com
Safe Sleeping With Your Baby from Dr. Sears