At the recent PlayStation day Sony released some nice pictures of the wireless buzzers. They use RF technology rather than Infrared, which means you don't have any line of sight headaches and they're backward compatible which means you'll be able to use them on your PS2 with any of the previous Buzz!™ games. The PS3 game will also accept the old PS2 wired buzzers meaning you'll be able to play eight player mode in Buzz!™: Quiz TV without needing to buy a second wireless set.
Batteries included, which give the buzzers a nice weighty feel.