In these post (post 1, post 2) I described how outgoing mail was hijacked while using a public wireless access points. I solved this problem by sending mail through a ssh tunnel. It looks like DynDNS is providing a service that accomplishes the same goal.
Their MailHop Outbound service provides an outgoing mail relay service. They provide this service on standard and non-standard ports to prevent mail from being blocked. Also they offer SSL connections to make sure your mail is secure. It looks like they are charging $14.95/year for the ability to send up to 150 messages a day.