Apple has just posted a new developer preview of Xcode 4, which reaches version 4. It’s available in the Mac and iOS developer portal.
This is a pre-release version of Xcode 4, a major new release of Xcode for both Mac and iOS development. This release requires Mac OS X 10.6 Snow Leopard, and includes the iOS SDK 4.1, to develop apps for Mac, iPhone, and iPad. Please review the Release Notes and Readme before installing this software.
Xcode 4 is a major new version of Apple’s development suite which sports lots of new features and a new single-windowed UI. The first version of Xcode 4 preview was released during the WWDC in June, the second build was seeded in late July, and Preview 3 was made available on September 2.