That is exactly what I was thinking of and waiting for
someone to mention it. There are many "Anonymizer"
Web Pages out there on the WWW that promise to relay
you through several third world servers before delivering
your Email. My company's Email policy also specifically
mentions that is also against our Electronic Communications
policy but then again, the company I work for practically
invented Email so that's understandable.
I sent myself an Email once or twice to check it out and it
worked. I wouldn't think you could hide something from
ECHELON though.
There are also web sites that specialize in breaking anonymizer.com and other anonymous proxies. I played with one the other night and it was able to break every proxy I tried. In addition, and this is most obvious, if your message has a return address or the source IP embedded it is dumb to go through a proxy. As far as I know, gmail does not embed the IP.