I'm not sure if you can use PS3 as an access point, but you can use PSP remote play to let your PS3 connect to internet and have your PSP stream PS3's web browser. So PS3 does the web surfing but you get to view the screen on your PSP kind of thing.

For Kai, there's very limited number of wireless routers that pick up ad-hoc signals, so you'd probably need a dongle for that (this may not be what you were talking about? but just in case).

 

I think Taziz has wired internet connetion hooked up to PS3, but no wireless connection for the PSP. So PSP leeching off PS3's wired internet connection seems like a good idea to me.