OnLive has announced today that their game streaming service will become available for the first time on June 17th of this year. There will be a $15 per month transaction fee with the cost of game rentals and purchases on top of the initial fee.
This first release will be for PC and Mac in the US only. There has been no announcement as of yet when a "mini-console" will become available for play on TV sets, or when more countries will have this service available.
This announcement is pretty surprising since it seemed like a distant idea for cloud computing to become mainstream. The cost seems like it may be a bit steep however, depending on what the cost of games will be on top of fees.