Apple has released a new version of their Xcode development environment on the Mac App Store. It costs $4.99, but members of the iOS or Mac Development Programs will be able to download it for free.
Xcode is used for developing both Mac OS X and iOS apps, and both groups of developers will see improvements to their workflow with Xcode 4. A new single window interface integrates debugging, testing, design, and coding into one panel. The Apple LLVM will also underline code mistakes as you type, and features automatic code correction for small errors.
Xcode 4 runs on Mac OS X Snow Leopard and includes the Xcode IDE, Instruments, iOS Simulator, the latest Mac OS X and iOS SDKs.
Whether Xcode 4, like previous versions of Xcode, will be bundled with Mac OS X Lion has yet to be revealed, though it's entirely possible Apple is hoping to trim down the disc contents and move entirely to online distribution. Considering the fact that Snow Leopard was focused on "trimming down" the OS but still included Xcode, it seems unlikely for Apple to reverse its stance on bundling Xcode.
Download From: Mac App Store ($4.99)