I just got a similar letter from my son, he passed at MEPS and was disqualified at bootcamp from his IS rate. I can't seem to get any information about what he can do, he was really wanting to be Intel.
reneeatlast - this is an old post from 2010 so it's not active. I'm not 100% sure on how it works (every case can be different) but most likely he will be given the option of another rate since he is already at bootcamp. It often depends on the needs of the navy. Hopefully you'll get another letter soon (with him telling you his new rate!) or he'll be able to call. Hang in there!