Mac OS X Snow Leopard (10.6) comes with JDK6 but I needed JDK5 for some project. I thought it would be easy to find and install JDK5 on 10.6 but it wasn’t and I ended up spending much more time than I expected to search for JDK5. Here’s what you need to do:
1. Download JDK5 for Snow and Snow Leopard from here.
2. Unzip and copy to /System/Library/Frameworks/JavaVM.framework/Versions
3. Use “Java Preferences” app and move JDK5 to the top of the list.

