Microsoft have realease The Windows 7 Release Candidate RC to the public, you can download it from HERE.
The install is pretty simple, and possible faster than any previous version of Windows. But if you’re having troubles then the guys over at LiferHacker also have a good Guide to Upgrading to Windows 7 RC.
I’m only using it for my media center PC at the moment, but I quite like it. The only reasons I’m not using on my main PC is that I don’t have allot of time to rebuild and tweak it, and it’s working quite well with Vista at the moment. Once the retail version comes out I’ll upgrade my main PC, but until then I’ll stick with Vista.