An ISP doesn't offer secure/encrypted POP3/SMTP connections to its email servers. (I could forward the mail to another mail service that does, but I'd like to try a proxy)

Is there some simple software that could be run on a linux box to allow secure SSL POP3/SMTP connections to it, and transparently proxy/connect to the ISP email servers? 

This is to allow wireless mobile devices more secure access their email without needing the full vpn.