Are you passionate about your work? Obviously most of us are. We talk to each other here about it all the time. Do to any dev group or hacker hangout and it's hard to hear yourself think with all the chatter we share with each other about our work.

Emailing, calling, or talking to civilians is the same thing. As soon as we think it's "selling", we set up a mental block that's no good for anyone.

Just build a great product for others and share your passion about that product with them. Anyone can do it. In fact, most of us already are.

Just be yourself, let others know how your work will benefit them, and let the "selling" become a byproduct of that process. It's much easier than many of us think if we just give it a chance.