The points-base trading model is not new, just look up Switchouse, Webswap, Mr Swap and Peerflix.
The Goozex service opened it's doors in July as did Gamershare, look it up and from what I can tell have about the same amount of user activity give or take the games that are available on Goozex...
I would recommend either Gamershare, which is free during beta release or Goozex but note these sites are pretty new.
Then you also have G2K Games, GameTZ, iTradeVideoGames and BegBorrow so look around, pick your poison and game away.