Here’s a neat idea for dealing with sites which won’t let you use them unless you provide a valid email address that they can then use to spam you. — 10 Minute Mail. Blurb reads:

Welcome to 10 Minute Mail. By clicking on the link below, you will be given a temporary e-mail address. Any e-mails sent to that address will show up automatically on the web page. You can read them, click on links, and even reply to them. The e-mail address will expire after 10 minutes. Why would you use this? Maybe you want to sign up for a site which requires that you provide an e-mail address to send a validation e-mail to. And maybe you don’t want to give up your real e-mail address and end up on a bunch of spam lists. This is nice and disposable. And it’s free.