Picking off emails is a sport of sort in Washington, D.C. My bro and I had email that ended up over at the eff-bee-eye as a result of his political affiliation years ago. Made me really paranoid for awhile.

If you run Gmail on a client (Outlook, Thunderbird, etc.), SSL is used for both incoming and outgoing mail. That makes it more secure than their web-based interface.

Try JanusVM for a quick off-the-shelf tunneling solution. I generally recommend it to folks wanting the security of a VPN but without the network resources. Be aware, it will slow your internet connection. iPIG is another one. Both would probably defeat your ISP, but who knows what lurks at those endpoints.

http://www.vmware.com/appliances/directory/1168

http://www.iopus.com/iPig/