Im gonna put out a full version and a free version of my game, the free version of my game will eventually have an IAP option added to unlock the full version. Will both versions be able to share the same leader boards on game centre? Thanks!
That is not possible. You need to have two different leader boards for two different games. After all, it does make sense.
I wish this were possible - it actually makes complete sense for this very purpose (this is all that is holding me back from releasing a Lite version). When Game Center arrives on Mac OS it actually will be possible to share Leaderboards across iOS and Mac versions of a single game: http://www.apple.com/macosx/mountain-lion/features.html#gamecenter So it seems crazy that two iOS apps couldn't also do so too - I am hoping this will change once Mountain Lion comes out and GC arrives on Mac.
My colleagues have already stated the problem. So I will occupy myself with outlining a solution. There are certain cross-platform leaderboard alternatives *cough*check the sig*cough* that may be able to help provide what you need not only by allowing for the same Game ID to be used to share leaderboards, but also on the IAP front if you end up taking the jump over to Android. [This is NOT a shameless and transparent plug; I'm providing a relevant answer to a legitimate question here!] *cat grin*