Go to Zune.net and sign in to your account (top right corner on the Zune software). Under your Zune Tag, click My Account. Click Manage Zune Music Pass. From here, you can change your subscription type or cancel your Zune Music Pass. If you cancel your Zune Music Pass, media usage rights will expire at the end of your current billing cycle. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.