Finanso.de:

Jetzt kann man beides kombinieren: Die eigene Email-Adresse und die Nutzung von Gmail / Googlemail.

Siehe in GMail Bereich “Settings”

If you’d like your outgoing Gmail messages to display another one of your email addresses in the ‘From:’ field (instead of your Gmail address), just follow these easy steps:

1. Log in to your Gmail account.
2. Click ‘Settings’ along the top of any page, and then select the ‘Accounts’ tab.
3. Click ‘Add another email address’ in the ‘Send mail as:’ section.
4. Enter your full name in the ‘Name:’ field, and the email address you’d like to send messages from in the ‘Email address:’ field.

*Keep in mind that each time someone replies to a message you send using a custom ‘From:’ address, the reply will be delivered to the ‘From:’ address rather than your Gmail address. If you’d like replies to be delivered to another account, you’ll need to enter a ‘reply-to’ address. Just click ‘Specify a different reply-to address’ to enter this information.