1) Best Buy, Circuit City, Walmart, etc. Forget EB/GS, TRU as they already sold out of their preorders. A good indicator is: if you see people waiting in line, chances are they are waiting for a PS3. YMMV.
2) I'm sure the store managers will know
3) When store will open... except perhaps Walmart which opens 24x7
4) You can try buying all but if you can get pass the people behind in the line in one piece... every store will impose a limit of 1 for such a hot item anyway