Two days after it released the first iOS 5.0.1 beta, Apple has released beta 2 of the same build for the OS. The original build apparently suffered from some bugs related to failed activations. Beyond those bug fixes, it doesn't look like iOS 5.0.1 beta 2 contains anything more than the original. The update comprises mostly bugfixes, the most important of which are bugs that are affecting iPhone battery life in a serious way for many users. It also adds multitasking gestures to the original iPad, which mysteriously didn't get the feature in iOS 5.
Developers can find the download in Apple's Developer Center, linked below.