Steve Ballmer, Microsoft CEO promised in his CES2009 keynote speech that Windows 7 will be available available for testing. This is the download link for windows7.
windowsteamblog has some additional tips-
> Available for a limited time to the first 2.5 million people who download the beta.
> It will be an ISO image – make sure you have DVD burner
> Free software is Imgburn from ISO image to DVD
> Windows 7 Beta version will expire on August 1st, 2009
> Join Springboard series
If you are worried that if Windows 7 may be buggy then try out installing this OS in Virtual PC mode –
Here is some useful info from Slickdeals –