Today Apple released the fourth version of it’s SDK to developers.

Differences include numerous API updates and OpenGL ES support.

The fourth beta version of the iPhone SDK includes Xcode IDE, iPhone simulator with Open GL ES support, Interface Builder, Instruments, frameworks and samples, compilers, and Shark analysis tool.

Release notes are here.

It’s 1.15GB and can be downloaded via the Developer Centre. I think Justin has the SDK, so hopefully he’ll report back soon !