Yes I know this was released yesterday before you say anything.
OnLive appeared a few months ago and it is a service that basically allows you to play the latest pc or xbox games over the internet. All that was previously needed was one of their tiny consoles or the program on your pc. Oh and some knowledge of forwarding ports on your Router. It all worked nicely and enabled you to play allsorts of games for a variety of different prices.
Yesterday OnLive released the Android app which is for phones or tablets. The app allows you to play any of your games you have already bought. Some games are touch enabled, some games have a onscreen controls and some games need a new controller. This is all done over wifi, 3g works but the delay is quite large and your phone network might not be too happy about rapid data consumption. You can even just go online and watch other people play the games before you buy them.
The one thing I spotted this morning was I had an email from OnLive and because I had downloaded the app and set it up they gave me Lego Batman for free. So to recap the basic account is free, the Android app is free, Lego batman appears on your account for free. All free so far. So if you fancy seeing what all the fuss is about the get over to OnLive and sign up and then get over to the Market for the app. Apparently it takes up to 24 hours for Lego Batman to appear.