I upgraded a similar Macbook a while back and can heartily recommend that you should do it. Even with the SATA bus not being able to take advantage of the faster SATA II or III speeds your macbook will boot up in seconds and operate much faster. Best "make my mac faster" upgrade you can do.
One thing to note, I experienced a REDUCTION in battery life when moving from the stock Apple HD to the OWC SSD. I ended up with about 3+ hours of usable battery life where before I had 4+ hours.
After installing the SSD it would be a good idea to reset the SMC as per this Apple KB article
When I first installed the SSD I was getting about 2 hours of battery life on a brand new (3rd party) battery. After resetting the SMC it went up to 3+ hours.