The latest update to SDL was released yesterday.
According to the release notes, this is a major release. They also highlight several OpenGL chnages and updates as well as major changes to the build system.
The most significant change for me is the ability to build Universal Binary applications for Mac OS X. This is possible using Xcode or traditional makefiles. This is great news for all Mac game developers.
You can always get the latest version of SDL from their download page.