Can you? Yes. Does it improve much? Sort of. Is it worth it? Ehh...not really.
The biggest improvement is with installing game data, that will go by much quicker than with the PS3's stock HDD. But other than that, SSDs offer only little improvement for things like in-game load times and texture pop-in. You'll only shave a few seconds off load times on average compared to a 7200RPM HDD. This is mostly because the PS3's SATA interface is SATA 1, which an SSD can't really take advantage of, plus lack of TRIM and other PC-related options that keeps SSDs running quick.