Chiming in with a bit of extra info, it's worth mentioning that the bulk of an SSD's benefit for the end user is not in its throughput, but in the IOP rate. Even on a slower SATAII interface, the drive can deliver its full IOPS capability, since that depends only on the controller within the drive, and not the interface between the drive and system.
So basically, even if you have SATA II throughput, the drive will still feel every bit as fast. The only place you'd notice the difference is large load operations, like games (which might make a half second difference in load times).