What mac OS X update should I get if I have version 10.5.8?

I got the new Iphone 5 and it says i need the Mac OSX 10.6.8 or higher to use Itunes and sync my phone? So exactly what software should I buy? Because i did notice Apple has Mountain Lion, Snow leopard, and lion. I'm confused in i want to update My Macbook as soon as possible.

10.6.x is Snow Leopard.

You will need Snow Leopard (10.6.8) before you can update to Mountain Lion (assuming your MacBook will run that) and so get that first…

http://store.apple.com/...ow-leopard