Microsoft has announced that the beta version of Windows 7 will be released for download on Friday (US time). In fact Microsoft is encouraging everyone to try it, and having seen a pre release version I would jump at the chance if I were you.
Windows 7, from what I have seen and tried thus far, is what Vista should be right now.
There is some great new features including integration with Facebook. For more info, have a read here.
For a list of where to get it and more detail, read on:
Download the BETA from here.
Note: This is a BETA release (ie test only, has bugs), so don’t replace your current operating system with this unless you have backed up all your data and are willing to do a fresh install of your existing operating system afterwards.