Microsoft released Windows Phone 7.8 update for existing Windows Phone 7.5 devices yesterday. While some users got their update through Zune, most of them were out of luck. Windows Phone Hacker has created a simple tool that allows you to update your device with few clicks.
The tool acts as a wrapper for the UpdateWP file, and contains all the updates and their language packs. Using this tool has the same risk as using the manual cab method, and is somewhat experimental, so use at your own risk.
Download it here.