Don't just get them rebalanced. You should get them road force balanced. This is a machine that actually simulates the vibrations that would be felt while driving..... Check this site out and find a place with a road force machine:
http://www.gsp9700.com/pub/search/findgsp9700.cfm
I had my tires balanced at good year before. The guy didn't even know what a road force machine was. He insisted that it didn't exist and balanced my tires. Well, it was complete crap. I looked up a place with the road force balancer, and my car is niiice now
.