Postfix Outbound Port 25 Blocked

[savage]

Hi all, here's my problem:

I have postfix setup, this was initially just to receive mail at my domain which works fine.

My ISP gAOL allow inbound port 25, but are blocking outbound 25, I'm in the process of setting up SquirrelMail, but can't send mail through it (AOL has identified this to be unsolicited spam email).

What I'm wondering is if I get an alternate port SMTP server on the net, can I get postfix to relay my outbound mail through it on the alternate port? If this is possible, does anyone know of any tutorials/documentation on performing this?

Thanks, Savage