Following the release of Apple's Mac OS X 10.5.3 maintenance update, the Cupertino folks rolled out the sixth

beta of the iPhone Software Development Kit (SDK). The first thing developers are required to do, in order to use the latest iPhone SDK release, is to download and install the latest version of Leopard (Mac OS X 10.5.3) recently issued by Apple.

The iPhone SDK Beta description hasn't changed, but the latest release (9M2192) brings an array of features and fixes: "With this software you can develop applications that run on iPhone and iPod touch. Includes the Xcode IDE, Instruments, iPhone simulator, frameworks and samples, compilers, Shark analysis tool, and more," Apple describes its development kit.

Weighing in at 1.19GB, the iPhone SDK is available for download right HERE. In order to download this application, you will need to log in with your Apple ID, but first and foremost, to upgrade to the latest version of Leopard.

"This beta release of the iPhone SDK is targeted to work only on Mac OS X 10.5.3 and is known to have compatibility issues on other OS releases, and pre-release software," Apple warns iPhone devs. "If you wish to run alternate versions of Mac OS X it is recommended you keep a separate partition for the iPhone SDK and its required version of Mac OS X," the company advises.

Some of the changes included with the iPhone SDK Beta 6 are highlighted below:

- The following samples have been removed from the SDK because their purpose has been duplicated by other samples or they are no longer necessary given additions to the SDK: ColorSlidingPuzzle, FingerSketch, GestureMatch, GLGravity, GLTeapot, Kalimba, Jigsaw;

- LPaint has been removed from the published samples while it is revised to use the new EAGL interfaces, transition to using nibs, and updated to no longer use the touchesChanged:withEvent: method;

- Data files are now preserved while uploading from Xcode for Run/Debug/Go. To clear your application's data and preferences, delete the application from the simulator UI;

- You can now add the view of a UIViewController to an arbitrary view.

The full changelog is available right here.

Apple is widely expected to showcase the latest iPhone firmware, as well as the new iPhone model, at its World Wide Developer Conference this year, probably using one of the first official iPhone 2.0 apps. Their respective developers have been confirmed to receive a piece of Kleiner Perkins Caufield & Byers' $100 million iFund.