I just want to chime in on this real quick: Vassal games
with Skype are MUCH more enjoyable (table-top feel, as Boba52 says) and much faster, and with fewer hassles, than Vassal games
without Skype. It only takes about 5 seconds or less for two people to connect a "call" on Skype. There's the odd situation where you lose the connection ("Can you hear me now?"), but even with something like that happening, it's still MUCH better than the alternative type-chat. There really is no question: using Skype for Vassal games is a huge improvement.
If someone doesn't have a mic, then obviously they can't do Skype, and so we'll have to resort to type-chat again for that match. But if we can affort to spend $100s of dollars on little lumps of painted plastic, then $20 for a mic doesn't seem too far out for most of us.
Furthermore, Skype is very easy to download and install--infinitely easier than Vassal and its associated maps!
I really hope that many of the players at this Saturday's tournament will be using Skype.