The FAQ for the OFA is here
You can do prelims on puppies over 4 months, but can't get OFA'd until 2 years old. It's $30-$40 to send your X-rays in to OFA. I just used my breeder's vet to do the X-rays, since that is who she always uses.
~ Diane in Okla
Carly ~ AKC Champion, GCh pointed, HIC
Sage ~ AKC Ch. pointed (13 pts - chasing that last major), HIC
Russell ~ the big boy
Mimi & Pi ~ the meezers