Hi Ben,
Creating VASSAL modules isn't terribly difficult for the most part - it's mostly a bit tedious or repititious, but there's no Java programming or anything like that to worry about.
One resource is a Webinar that Brent Easton put on (mostly), I finally got my internet working and joined in but Brent provided most of the good information. You can download the archive
HERE.
As I mention in that Webinar, how I learned was to simply download a module for a game that I knew closely resembled the one that I wanted to make a module for and I opened it up in the editor and had a look around. If you do so, you'll find that you'll see a heirarchial list of elements that make up the module, something like:
Where you'll see that you have the help menu, the map window, pieces and charts basically. Those each expand and that is where you add the map and pieces and charts obviously. To the map you can add a hexgrid and numbering. To the pieces, you can add traits such as "mark moved" or rotate, etc.
I figured things out by adding new stuff to that module - not neccessarily things that really belonged in that module, but I just wanted to see what things did. I'd suggest doing the same.
The 2nd reference is the most important one and that is the help files that you'll see when you click on the little greenish "?" button (third button on the right in that screenshot). In there is instructions on how to use each component that makes up the module. It may be a bit lacking at times, but it's really all there once you start to tinker with it.
The 3rd reference is the Yahoo! mailing list at
VASSALENGINE. There's a number of folks that are ready, willing and able to answer any technical questions that you might have, so you'll want to subscribe to that list.
Finally, as far as GMT Games goes, I just published a module for Ardennes '44 (as that screenshot shows) with the permission of the designer/developer. In fact, he even sent me some of the original artwork for the counters that went to the printers, so that really helped. I'd find the email address of the developer of the games you're interested in and jot off an email. I've found that for the most part, they actually are flattered that someone wants to invest the time to do a module for their game. There are exceptions of course, but generally I've had success each time that I jotted off a polite email.
Oh, one other part is the artwork - you'll need a scanner and will need to scan the map and counters of course. Many people have good scanners and they just crop and put those scans into their modules. My scanner sucks and frankly, I love doing the artwork, so I just redraw it using the scan to trace over. Either way, depends on your proficiency with something like Photoshop or Paint Shop Pro or The Gimp.
Give it a whirl, the more people making VASSAL modules the better! You'll only get better at it the more you make, so open up the editor and start tinkering!
