Remote Desktop or Streaming Software/Services that Supports Gaming

The real revolutionary aspect of Onlive is the low latency they effect in their client system. If you are racing around a racetrack in Forza you definitely don't want to have to deal with a 250ms time gap between sending a brake command, and the brake command being rendered on your screen. Onlive is such a big deal because it was thought impossible by many on residential bandwidth up till the CES where it was unveiled, and still by many for a while afterwards.

Nearly all remote desktop solutions, prefer heavy security on the connection to a particular need for low latency. Windows remote desktop has noticeable latency issues for signals as simple as audio. The primary purpose of almost all remote desktop services is for presentations and technical support, and latency is of very low concern for those.

The world will be a better place if Onlive ever opens up their technology. In the meantime, I'm not optimistic about your options.

The following are possible candidates :

TrueRemote
NeoRouter
2X-Client Portable
ZeroRemote (older version of TrueRemote)

I cannot vouch for any of them, as I am not a user of remote games.