Following today's GDC keynote from OnLive CEO Steve Perlman, his COO, Mike McGarvey, fielded questions about the game streaming service that's launching June 17. Unfortunately, just how much full games will cost on top of the $14.95 monthly subscription fee was not one that he answered.

McGarvey did confirm that the service will launch with a lineup of titles "in the teens," comprised of some that will have been on shelves for a few months -- Mass Effect 2 and Dragon Age: Origins were examples -- and others that will release closer to OnLive's debut, such as Prince of Persia: The Forgotten Sands. The catalog will grow from fewer than 20 games on day one to "50 to 60" by the end of 2010, according to McGarvey. These (and all) games on the service will be playable "for years" after release, he said, addressing concerns that buying a game "hosted" by the company could be a risky investment.

Some details are being saved for an announcement at or leading up to E3, including when the OnLive micro-console will be available and, of course, game pricing. McGarvey would say that the company is looking to offer incentives (free games, perhaps?) to build the subscriber base, and that those who sign up "may get some free content" for the monthly fee ... at some point. The micro-console may also be offered free with a service commitment, McGarvey stated, though it will "potentially" be sold on its own.

Saying that more than 250,000 people signed up (but weren't all accepted) for the OnLive beta, McGarvey admitted that the company expects "demand will far outweigh capacity" for the service's launch -- we'll be interested to find out how many people actually "pre-subscribe" and if the company changes its outlook leading up to mid-June.