The Hawgleg site has a tutorial on using Amazing Mold Putty and Amazing Casting Resin to make models. The two products are available at stores like Hobby Lobby
Modeling
Modeling A Shack From Scraps
This is a great video on modeling an abandoned farmhouse or shack for your wargames table.
Using Teddy Bear Fur To Make Grass
The Earlswood site has instructions on using teddy bear fur to make patches of grass for your miniature wargames terrain.
Making CD Based Scatter Terrain Bases
Making Simple World War II Buildings
Matakishi has some instructions with photos for making World War II era buildings out of sheets of cork.