Apple has released a second version of its iPhone SDK. It is available immediately as a a 1.3GB download to registered developers on Apple’s developer site and it features Interface Builder, Xcode IDE, Instruments, iPhone simulator, frameworks and samples, compilers, and Shark analysis tool.

The Apple SDK ships with firmware 1.2, which can be run via an emulator. Firmware 2.0, with all the enterprise functionality, was only made available to corporate testers already installed on real iPhones.