One little gem for gamers at WWDC today is a new Game Center for OSX that will allow players to play with friends on iOS when games are available on both platforms.

Combined with pixel-for-pixel mirroring that was also announced for the new version of Mountain Lion, this is going to be pretty sweet. The WWDC demo showed CSR Racing playing on an iPad against a user on a MacBook.

Apple also took the opportunity to boast that they've got over 130 million accounts, 5 billion scores posted per week, and that 67 of the top 100 games have integration. Also, you can now explicitly challenge your friends to beat your Game Center high scores.

More news coming out of our WWDC keynote liveblog as it happens!