In his blog, Ed Bott shares an excellent summary of licence changes associated with Windows 8

Windows 8 – new licensing terms

QUOTE:  What’s changed in Microsoft’s radical new license agreements for Windows 8? I’ve got full details about how you can transfer Windows to a new PC, downgrade rights, and who qualifies for upgrades.  I’ve had a chance to inspect the new, radically revised Microsoft license terms in advance of their October release. Earlier this week, I noted the two big surprises: All of the agreements are written in plain language that’s surprisingly easy to understand, and Windows 8 will, for the first time ever, include a new Personal Use License that explicitly permits retail customers to install and run OEM System Builder software. The overpriced full package products will not exist for Windows 8.