Persona 4: PS2, Vita, & PS3 Differences

So I'm thinking about starting Shin Megami tensei: Persona 4 for the PS2 but then I searched and found out that Persona 4 Golden is coming out for the Vita soon as well as persona 4 Arena for the PS3; Now, can someone please explain the differences between these 3 games, are they all the same with just updated graphics or are they more like Persona 4.5 sequels? kinda like the portable Kingdom Hearts games.

Persona 4 Arena is a fighting game made by ASW that takes place after P4. Persona 4 Golden is Persona 4 touched up for the Vita.MethodManFTW

Thanks!