Yeah, something is bent/broken. Things that come to mind, besides what stazi said, are:
Broken/bent suspension arms: any of them, espcially the rear. (does it feel out of alignment)
Broken front swaybar/mounts/endlinks (does it roll a lot more?)
Really messed up tire pressures (should be 32 all-around for a stock-ish car)
Could you describe the problem in a little more detail? If you jack it up and can't see anything wrong, a synopsis of the vehicle's handling characteristics would help significantly in a diagnosis.
