I have my Gmail linked to non-Gmail email accounts so that I can send mail as them. Is there a way to use this feature without the web interface (smtp)? I use Mail for Mac OSX Snow Leopard.
Is it possible to utilizing the Send mail as Gmail feature from SMTP?
gmail;email;mac;smtp
[Edited, see comments]In the Mail application you'll want to add a second (or third, etc. if you have more) SMTP account.  Then, when composing an email, you can select which account from which you wish to send it.  More information:http://www.macosxhints.com/article.php?story=20010401111133239