To create a "disposable address":

Since you'll probably be creating multiple disposable addresses and then deleting them as they get spammed, it's best to begin with a base name (such as "shopping") that's different from your primary address. To get started, go to the "Spam" section in the "Mail Options" page and then select "AddressGuard." Next, click "Create a Disposable Address."

After you've created a base name, click on the "Add" button under "Disposable Email Addresses" and type in an appropriate keyword (such as "shoes") for this particular address. Click "Continue."

Use the pull-down menu to determine where messages sent to this address will be delivered. You can create new folders if you wish. Click "Set Up AddressGuard" when you're done.