Not sure if these are relevant still or not, but this seemed like a good place to mark some of the things I've found over the past month while surfing the internet.
The best place to get the game itself. Look for "Warmaster Living Rules" :)
The Specialist Games forums - this is a link to a lot of what I have below:
THE most inspiring Blog I've found on Napoleonic building as
mini-dioramas - and because of this, my wallet went KA-BLAM over at
Total Battle Miniatures and Levin Miniatures!
Campaign rules and a repository of Warmaster rules supplements
This seems to be a fully functional army builder online, with links to some of the Warmaster PDFs.
This guy has some neat entries on terrain and Warmaster units he has done.
Another repository of Warmaster files, including counters for gaming
In case you don't have models and want some counters to play with:
Some reviews of 6mm Buildings
A fantastic PDF on making small-scale forests - like, FORESTS, not individual trees clumped around each other :)