@The Stone: Big THX for sharing, this serialization works perfectly.
I've tested it on the iPad with Unity 3. You can use it the exact way, except you have to choose carefully where to save and load the file, because you only have restricted access to the device's folders.
For me the Application's "Documents" folder worked very well:
Stream stream = File.Create(Application.dataPath + "/../../Documents/" + "MySavedGame.game");
Use the same path for loading.