I got one of these BTW. Works really well on both the PS3 and Xbox 360. With the PS3, it is correctly detected as a USB KB and USB mouse. No mouse support on the 360 obviously.
It's smaller than a laptop KB, and surprisingly ergonomic. It's curved to fit over your legs (sits on your lap nicely when on a chair/sofa) and the trackball/mouse buttons and scrollwheel are in good positions in the upper left and right. Some keys feel a bit stiff at first, the arrow keys are on the narrow side, and the optical trackball is a little rough and sensitive as compared to a mouse, even with the PS3's "slow" pointer setting. Besides Enter, the arrows, ESC, F1 is the only other key which does anything - it brings up the Browser's Toolbar. KB/mouse all work on the store as well, and the KB (arrows/Enter) works with the XMB Sony needs to add more keyboard shortcuts for browser control though.
The USB dongle actually matches the PS3 and sticks out just a little past the front of the console. Packaging is a little cheap, but expected. It's 2.4ghz, and didn't exhibit or cause any interference that I noticed.
It's great to just leave off to the side and quickly grab to send a message, or check out your email or browse.
Seems like a nice alternative to the $100+ bluetooth sets out there. Some 3rd party should make a BT version with the PS3 in mind.
/quick review