Retro City Rampage, one of the PAX 10, its creator Brian Provinciano revealed to Joystiq that the game would likely launch in December of this year. Up until now, all we had was a tentative Q4 2010 window -- Provinciano nailed the last month of the year as being an optimal time to subject the world to his experiment at seeing how many inside jokes he could fit into a single game.
WiiWare is currently the only platform, though Provinciano noted that he was currently "in talks" with Microsoft on bringing the game to XBLA. PSN was also on the table, he offered. A PC version would be out of the cards for "at least a year."
Provinciano began the game as Project Grand Theftendo, where he sought to create an 8-bit version of Grand Theft Auto 3 that ran on the NES. We'll have a preview of the game soon.