ExtremeTech did a test with solid state disk in an attempt to speed up start and load times on the PS3 console. It's definitely a tad faster but not really cost-efficient.
Okay, so the long and short of it is this: Swapping out that PS3 hard drive for one of Intel's X-25 solid-state drives won't do much to improve install times from game discs, but it will improve install times from downloaded games and most game startup and load times by anywhere from 25–40%, depending on the situation.
That's a huge improvement, but is it worth it? This 80GB drive costs in the $660–700 range, which is considerably more than the PS3 itself. Considering that the base PS3 model these days is the $400 unit that already has an 80GB hard drive, you're not even trading up to higher capacity unless you happened to buy an older 60GB unit or the bargain 40GB unit.