Apple has made the 4th beta of it's iPhone SDK (Software Developers Kit) available to iPhone developers. The new version of the iPhone SDK has support for OpenGL ES for the iPhone emulator that is included in the SDK. Before the support for this came out, to truly and reliably test iPhone applications, the developers would have to load the application onto the iPhone.

You can download the new SDK by visiting the iPhone Developer Center. The new SDK weighs in at 1.15GB, so if you have a slow connection, you should probably get that download started so you can begin playing with the new SDK by morning.

"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.

From the iPhone SDK change log

Apple also took the opportunity to drop a new firmware build 5A258f. It is of course only available to select developers. It is not known if the Pwnage Tool, in it's current form, will work. It could take a little while for the Pwnage Tool to catch up with the new firmware. The firmware file is 200MB, much more bandwidth friendly than the SDK.

Please check back soon for hands-on review of iPhone firmware 2.0 5A258f.