Neowin has some hints on how to  legally get Windows 7 at a discount or even for free when the final version is ready later this year:

1. Between June 26, 2009 and January 31, 2010, any new computer purchased with Windows Vista will qualify for a free upgrade to Windows 7. So if you've been planning on purchasing a new PC in the near future, you should hold off just a little while longer.

2. Check and see if your school is with the MSDNAA or Microsoft Developers Network Academic Alliance. If they are, check with their specific MSDNAA site when the final version of Windows 7 comes out to see if they distribute it.

3. Check with Microsoft DreamSpark. This is a special site from Microsoft that gives out free software to people who have a valid e-mail address from any of the qualifying schools listed. It's possible they could put Windows 7 up there once it's released.

4. If you're in the US, Canada or Europe, and are in school, there's a site called Journey Ed that gives out software and other kinds of products at a discount. You just need to show them some kind of proof.