MASGAU uses the GameSave.Info XML 2.0 format. That link should provide all the info you need to add your own games. Unfortunately, it's a little complicated! To counter this, MASGAU includes an analyzer component, which (with your help) automatically scans your computer for all the info needed to add a game to the GameSave.Info database (which also means adding it to MASGAU)! It'll even e-mail it to me with the click of a button!