You'll have to flash your phone first, but I have to stress you do so at your own risk. Just like installing the leaked OS, it's a bit risky, so I can't blame you if you'd rather wait for an official version. It should be here in a matter of weeks rather than months, if Microsoft is to be believed.
If you do fancy chancing it, it's Firmware build 8858 you want. You'll need to download Navifirm first, which you can do from Symbian Toys.
So why upgrade? Well Windows Phone 7.8 has some of the same features as Windows Phone 8. These include resizable Live Tiles, a new Start screen, new Accent colours, and different icons for Xbox, Office and Store. Other additions include Bluetooth sharing, a full two dozen backgrounds for the lock screen, and the option of choosing Google as the default search engine in Internet Explorer.
According to a statement at the end of last month, Windows Phone 7.8 should be with us in an official capacity early next year. Microsoft said it was "working closely with our hardware and carrier partners to get it tested, approved, and rolled out to as many devices as possible in early 2013."
Those who have taken the plunge are so far reporting good things, with few experiencing any bugs. But again, I must stress that if you choose to follow their lead, you do so at your own risk.
Are you looking forward to Windows Phone 7.8? Let me know in the comments, or on our Facebook page.