IOS 5 beta 2 Update iPhone 4/3GS, iPod Touch 4G/3G & iPad 2
The IOS 5 beta 2 has been released and updated download link is now available in Developers Area with Apple Portal. iPhone 4 / 3GS, iPad and iPod touch 4G / 3G user can update onto IOS 5 Beta 2 at your own risk because the updated version of software / firmware is still in testing phase and offered to the developers for preview. So the it is not fully recommended to update onto the Beta version of IOS 5.
How every few of the developers have placed the provided links on their private downloaded links you can try those links as well but risk will be your again.
Official Download Link of IOS 5 Beta 2 (you can download this if you are developer at Apple)
Un-official Download Links for IOS 5 Beta 2 are simply not recommended at all