It might be copyright infringement, or they might have a license.  Given that they don't have (as far as I noticed) a copyright notice indicating the ownership of Pacman, then they probably don't.

Someday, sooner or later, Namco will find them (if you did, they will) and will slap 'em with a cease & desist letter, I'm sure.

John
http://www.livejournal.com/users/fiala_tech/