Similar keyboard conniptions on my MBP after the recent Snow Leopard update. Obviously, it being a MBP, this wasn't a wireless issue, but directly after installing the update, the keyboard refused to type a word. I could place the cursor with the mouse but the keyboard was totally non-reactive.
Re-booted it. Didn' t work. Ran Disk Utitlity, verified the disk, verified and repaired disk permissions and then did another restart. After 10-15 secs of further inactivity, the keyboard started working again.
There seems to be a problem relating to keyboards on the most recent Snow Leopard update. Disk Utility and a couple of restarts seems to have ironed out the wrinkle.