I generally always raise preflop with pocket aces. Sometimes I want to slow play them to try and win a good pot...but too often, you will lose them that way.
I will raise big enough to try and get everyone to fold (usually 5xBB). If my stack is low, I will simply go all in. It's the best hand preflop, so you have to play it like it is, especially when you need to gain some chips.
If you get called by 3 or more people, it's time to worry though. It seems like with 4 ot more people in a hand, pocket pairs rarely win. Someone always catches a straight or 3 of a kind.