Do you hear clicking noises when you turn?
Check your front suspension to make sure it'
not damaged : press down on one side and release it, it should stop bouncing (oscillating) after 1 or 2 bounces. It could also be your wheel bearings.
I think the best thing you can do, if you're not the do-it-yourself type when it comes to cars, is to get it checked out at an AAA (or CAA) approved garage. Be sure to note in advance that everything else works FINE and you have no intention to do any other repairs/tuneups. Mention that you'd like them to take a look a the front wheel/hub bearings, the guy will think you'll know whats going on and you'll have less chances of being fucked over.
gl with that