California startup OnLive plans a June 17 launch for a service that streams videogames over the Internet, meaning players can avoid buying expensive consoles or packaged software.

OnLive expects the US roll-out to feature blockbuster titles such as "Mass Effect 2" and "Assassin's Creed 2" which have been major hits with players using Sony PlayStation 3 and Microsoft Xbox 360 videogame consoles.

"This marks a huge milestone for both OnLive and the interactive entertainment landscape as a whole, changing the way that videogames are developed, marketed, accessed and played," said OnLive founder and chief executive Steve Perlman.

"We are opening the door to incredible experiences for gamers and enormous opportunities for developers and publishers."

The news came during a Game Developers Conference where start-ups such as InstantAction and Spawn Labs were among those taking videogames into the Internet "cloud."

"This is a really exciting time for the industry," InstantAction chief executive Louis Castle said in a video posted online Thursday.

"We are seeing these new technologies for distribution and customer sharing that are really great. The industry is going through some monumental changes."

InstantAction lets people play games in the Web browsers, as well as share or embed them in emails or at online social networks just as they would a video or photo.

Players can pay as they go instead of buying entire games or "all-you-can-eat" monthly subscriptions.

"We can give you little bits and pieces of it as you are playing," Castle said, referring to progressive downloading that delivers software as needed depending on where players are in games.

"That really is the way of the future. It would be nice if we could go into a movie theater, watch the first 20 minutes of a film and then decide if we want to watch the rest."

InstantAction launched with support for Macintosh and on personal computers running on Windows operating systems and plans to roll out games in coming months.

LucasArts announced at GDC it is using the InstantAction platform for online distribution of a "The Secret of Monkey Island: Special Edition" videogame to launch soon.

Games bought at InstantAction remain saved on that company's servers, so players can access them from any Internet-linked computer.

"Once you've paid for that game you own the game," Castle said. "Log-in anywhere and you play it."

The platform will expand to serve videogames to mobile devices later in the year, Castle said.

InstantAction is not hosting games for Xbox 360 or PlayStation 3 consoles but "certainly could do that in the future" because those devices link to the Internet, according to Castle.

Spawn Labs at GDC was showing off computer game innovations based on using peer-to-peer networks to make online game graphics more seamless.

"We believe the peer-to-peer approach offers major advantages," Spawn chief executive David Wilson said Thursday in a release.

Peer-to-peer networks use strings of users' computers to process and store data while cloud services such as OnLive host programs at privately owned data centers.

OnLive in March of last year revealed it was building a library of videogame software on servers that players reach over broadband Internet by using mini-programs in home computers or OnLive MicroConsoles connected to television sets.

Comparable in size to decks of cards, MicroConsole devices will be provided free with videogame services that let people pay monthly subscriptions to play online.

The subscription service will be priced at 15 dollars per month at launch, according to OnLive.

Graphics of game play are streamed to players while the interactive software remains secure on OnLive computers to eliminate piracy concerns.