Apple has released the fourth installment of its iPhone SDK Beta. The highly anticipated development kit for the iPhone, officially launched on March 6 as a free download for anyone looking to work some iPhone code magic, now includes Xcode IDE, iPhone simulator with Open GL ES support, Interface Builder, Instruments, frameworks and samples, compilers, and Shark analysis tool.

Apple confirms that using its iPhone SDK, developers, big and small, can produce applications that run natively on the company's touchscreen and accelerometer-enabled devices, the iPhone and the iPod touch. In order to download the iPhone SDK (1,4 GB), you will need to log in with your Apple ID. The download is free of charge.

Once you've got something going on, you can give it a go in the iPhone Simulator on your Mac. However, if you want to test your code directly on iPhone and maybe even distribute your application through the upcoming AppStore, you'll need to apply to the iPhone Developer Program ($99).

"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," Apple states on its website.

Requirements call for an Intel-based Mac running Mac OS X Leopard.

Apple has recently said yes to more iPhone devs who applied for the iPhone Developer Program. Apple's CEO officially stated during the iPhone Software Roadmap event in Cupertino, March 6, that the program would be available only to a "limited number of developers" in its early stages. Jobs also implied that, as v2.0 iPhone software approaches, more developers will be taken aboard.

The final version of the firmware is expected in June as a free update for iPhone users. iPod touch owners will be required a small fee for the upgrade, as usual.

Click HERE to download the iPhone SDK Beta 4.