It depends on what you want, if you want latest stock firmware look on sammobile.com.
If you want an alternative firmware you could go for Cyanogen Mod 7.2, you'll find it here in the developers section along with other mods.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?