The Chillstream for PS3 will indeed function on PCs. They will use the built-in HID drivers. In fact, all of the buttons should function just fine on a PS3 (There is no PS button on the chillstream for PS3: It's hardware development was completed before the PS3 was released, and Sony announced last-minue additions to the PS3 controller. I'll spare you the details, but some final-spec controller additions, like the PS button and motion sensing, were not added to the controllers.
As an interesting side note, since these are completely standard HID controllers, they actually work great on PCs. I cannot promise they will function perfectly with specific games (Especially Games for Windows games: They sometimes have very iffy HID controller support), but I can tell you that I have personally used the Chillstream for PS3 on PCs and Macintosh computers without problem.
