Thunderbird

Mozilla Thunderbird has first-class support for identities; setting up your forwarding address is pretty easy, just follow the steps below. The screenshots were taken from Thunderbird 2.0, but the instructions apply for version 2 and 3 of Thunderbird. We assume you have already set up your primary email account with Thunderbird.

1. Open Thunderbird.
2. Go to the Edit menu, and select "Account Settings".
3. Select your main email account from the accounts column, then click the "Manage Identities button.
4. Click "Add..." to add a new identity.
5. Fill in your name and End Slavery Now forwarding address as your email address, and click "OK".
6. Congratulations! You're all set up. Now, when composing mail, you can choose whether to use your original account identity or your End Slavery Now forwarding address by choosing the address in the From dropdown.