Disposable Email Addresses - I think this is cool. Spamgourmet will provide you with multiple disposable email addresses that only last for a specified number of messages, and then expire. Perfect for handing out for temporary applications you don't trust. And once you sign up, you don't even have to return to the site to create new addresses - you just hand out an address and it starts working automatically.

There are more advanced features, but those explanations are better left to the site itself. Check it out. No more having to put *nospam* in your email address when you post somewhere.