You need a receiver with an amp to drive the speakers. You can buy a receiver and speakers separately or you can buy a receiver-based home theater bundle. Since you already have a Blu-ray/DVD/CD player in the PS3 you want a home theater bundle that is based on a receiver rather than a player. These are more flexible for expansion should you want to upgrade receiver or speakers in the future and have far more connection options. The Onkyo HT-S3200 is a solid entry-level package, but in my opinion the best thing going right now is this:
http://www.amazon.com/Yamaha-RX-V365BL-5-Channel-Theater-Receiver/dp/B002FJ3TYI/ref=sr_1_7?ie=UTF8&s=electronics&qid=1246412031&sr=1-7
It's a good set of Polk Audio 5.1 speakers and a solid Yamaha 5.1 receiver for $397.
P.S. You want a 5.1 setup--5 speakers and a subwoofer--because that's the soundtrack on most movies and games.
http://www.amazon.com/Yamaha-RX-V365BL-5-Channel-Theater-Receiver/dp/B002FJ3TYI/ref=sr_1_7?ie=UTF8&s=electronics&qid=1246412031&sr=1-7
It's a good set of Polk Audio 5.1 speakers and a solid Yamaha 5.1 receiver for $397.
P.S. You want a 5.1 setup--5 speakers and a subwoofer--because that's the soundtrack on most movies and games.