QuickInbox Disposable E-mail
QuickInbox disposable e-mail service has released it's very own Firefox Add-on that simply adds a menu item when completing a registration form so you can right click and generate an @quickinbox.com disposable e-mail.
https://addons.mozilla.org/en-US/firefox/addon/146351/
There have been about 450 installs already and the plugin has about 100 active daily users. If you think you'll ever have any need for a disposable e-mail it's highly suggested!