I think letting people know that they shouldn't expect to see you drinking and know that you are in fact committed to not drinking is key.
You've created a whole grip of people who will understand and think nothing of it when you're not getting railed at the bar and just having a good time with your soda
That can help alleviate a lot of the pressure and awkwardness.
Sure, a great many people like to get blitzed at these events and its one of the reasons they're so fun and the industry itself is such a casual and friendly one to work in. But I find that when I actually peek around to take note of the people who are just having one or two, sippin' on soda, or have really mellowed out their drinks since the first night (as Lee mentioned, which I think a great many people do as well), there's a whole lotta em.
Myself included. It's been some two and a half odd years since I last had a sip of booze and I love the conventions and webmasters events.
Now if I could only find the number for Twink Lovers Anonymous...