I heard that there are going to be 2 types of XIII but I am confused on what the difference is between Final Fantasy XIII and Final Fantasy Vs XIII or whatever its called can somebody help clear it up for me.

firstly there are 3, 2 for console and 1 for mobile.
secondly they are completly different games with completly different stories the only thing that is the same is the mythology in the games. FFXIII is being done by the FFX team and VSXIII is being done by the kingdom hearts team

They are in the same world, yet totally unrelated characters and storylines.

you know, you could have searched a bit and found the answer to your question without making a thread

So what the hell is Final Fantasy Versus XIII then? We're glad you asked. The XIII games - there are several on the way, including the less than thrilling mobile phone version Agito XIII - all come under the Fabula Nova Crystallis umbrella. Versus XIII is an altogether darker retelling of the universe, starring a young chap (he's royalty, apparently) with (almost inevitably) blue hair. We;re told it won't be an online counterpart to XIII, but an extension of the universe in the form of a more action-based RPG. Don't panic though. There's a good chance it won't be a Dirge of Cerberus-style mess-up, because development is being done by the Kingdom Hearts team, and although we're told it will play differently to the Disney-based RPGs, they've got the talent and invention to pull this kind of caper off.