Apple has just released another iPhone 2.0 OS update and the third beta for its iPhone Software Development Kit (SDK). The third beta version of the iPhone SDK includes Interface Builder, Xcode IDE, Instruments, iPhone simulator, frameworks and samples, compilers, and Shark analysis tool. The updated iPhone 2.0 beta firmware (version 5A240d) delivers fixes and improvements around Microsoft Exchange support, MacRumors informs.

Using the iPhone SDK, you can develop applications that run on iPhone and iPod touch. Once you've got something you can give the app 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).

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

KPCB's iFund, announced at Apple's March 6 event, is a $100M investment initiative that will fund market-changing ideas and products that extend the revolutionary new iPhone and iPod touch platform.

"A revolutionary new platform is a rare and prized opportunity for entrepreneurs, and that's exactly what Apple has created with iPhone and iPod touch," said John Doerr, Partner at Kleiner Perkins Caufield & Byers. "We think several significant new companies will emerge as this new platform evolves, and the iFund™ will empower them to realize their full potential."

Also, 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.

The iPhone SDK (Beta 3) is a free download.