Try VeloSport on MLK at Virginia. That's where my son's first helmet came from. He has a big head, but he started wearing it when he was about 6 months old. I'd consider selling or loaning it, but it was in an accident. The brand was a French name (man's name, first and last--Louis Varnaux?).

I bought the smallest one I could find when my daughter was about that age (9 months) and then stuffed extra socks into it because it was still 'way too big. In retrospect it would seem that socks would reduce the efficacy of the shock-absorbing properties so this was not necessarily a good thing to do. I just couldn't find a smaller helmet.

From: Craig

Oooh! Not a good idea. I think most doctors will tell you (they told me) that you should wait until they're at least a year old. The problem with putting a helmet on too soon is that their little necks just aren't ready yet and the added weight of a helmet can actually cause serious injury (i.e.. you stop short for some reason and they might not be strong enough to stop their head and helmet from whipping forward too fast). Most helmet companies don't make really small helmets for this very reason.