AT&T just joined Apple in shipping out iPhone 4s.
I'm seeing tipsters' order dates of both 6/15 and 6/16, but I'm not sure if those 6/16 were ordered on 6/15 or not. But yes, we know now both AT&T and Apple are shipping iPhone 4s. So please, enough with the tips on this particular subject. [Thanks tipsters!]
Update: Reader Chris says that he ordered on 6/15, but his says 6/16. Probably just a late entry in AT&T's logs.