Thats about right. Max distance under ideal conditions is about 30 feet or 10 meters. Things like walls, other devices with similar frequencies, etc., can shorten that considerably though.
I connected my PowerBook to the TV today to watch a movie (yeah, I was too lazy to burn to a DVD!!)
and I got out my wireless mouse and Keyboard so I wouldn't have to stand and stuff.
I was a good 30 feet away. Aww yea. (accd. to conversion widget, that's about 9 meters)
EDIT: Good golly! 30 feet, 30 feet**** I can't type! Not 40! (although, that'd be sweet)