Apple on Tuesday shipped the fifth release of the iPhone SDK.

The latest version is available to registered developers from Apple's iPhone Dev Center (log-in required). Apple says the new version SDK ships with updated documentation, the latest release notes and more.

Apple this week also began accepting new members to the iPhone Developer Program from outside the U.S., which allows access to pre-release iPhone software (i.e. iPhone OS 2.0); technical support; the ability to get code onto iPhones for testing; and distribution of applications via the new App Store.

Apple will host WWDC 2008, with a dedicated track for iPhone developers beginning June 9.