The best feature added to iPhone OS 4.0 was its multi-tasking functions. In the iPhone OS 4.0 beta 3, we get to see Apple’s multitasking functions, which include quick access to iPod controls and screen orientation lock for either portrait or landscape mode. If you want to access the new features on iPhone OS 4.0 beta, just flip to the left of the first window of apps. The quick access iPod control is very useful to change music tracks and stop the music any time without getting into the app.
Apple has removed the beta 3 download of iPhone OS 4.0 temporarily, so if you wish to download, you won’t be able to download. Developers has also reported some issues with the iPhone OS SDK installer.