actually what's interesting, it seems like over 50% of low level players will always MIN raise with AA/KK, they reraise you the munimum, that should send of a few alarms.
They do this because instincivley they know they are probably a favorate to win, they want you to stay in the hand.

If he reraised you a lot he may be protecting a hand like JJ, QQ, TT, AK, AQ etc...
On the contrary, they raise higher with these hands (especially the PP's) because they are afraid to see an A/K or some type of overcard on the flop.

All in preflop AA/KK is how most players go broke ( because its generally the correct play)