Yes it does work with the PSP, but make it sure it says ' Sony ' on the stick itself. But i heard it's a whole lot slower then a 4GB. It's better off just buying 2 4GB's rather then 1 8GB since..it's slow, and the loading times with it slows. Like when you look through it on the PSP itself, it takes longer to see the little icon and stuff..
I agree with the above. I have both an 8gb and a 4gb, and the 4 does load faster. Its noticable, but not too big of a problem. If you like to speed through with things get the 4s, otherwise the 8 should be fine.