Of you didn't find it already go to samfirmware.com and register for free and see if you can find there. Do a search for S-7500 or if you have one of those localised versions(I think there is L and one more can't remember which). You will need a program called Odin.
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?