BleepingComputer.com: Guerrillamail

Guerrilla Mail provides you with disposable e-mail addresses which expire after 15 minutes. You can read and reply to e-mails that are sent to the temporary e-mail address within the given time frame.

generates random disposable email addresses. Use these email addresses for registration in forums, adult sites or whatever.
The email addresses don't require any registration. This is an easy way to avoid spam, because the spamer will never know your private email address .. only the temporaryinbox.com email address. And there the emails will be deleted after 6 hours.

Create free disposable email addresses and paste them directly in forms. This helps to protect you from spam mails and could be useful when subscribing to forums or newsletters.
The email addresses can be deleted at any time!
This version supports now plus addresses, and multiple domain name if trashmail.net is banned on a website.
To all users who were victims of services which bans the domain name @trashmail.net:
Try as alternative with this domain name:
@fakemail.dyndns.org