The Mordheim in Montana blog has an illustrated article on making bushes and shrubs for your 25mm wargames.
modeling
Making Expanding Foam Hills and Rock Clusters
Here’s a nice tutorial on making cheap and easy expanding foam hills for your wargames table.
Building An Inexpensive Game Board
Here’s an instructional video on building an inexpensive game board.
Modeling Trenches
Here’s a video tutorial on modeling trenches.
Making A Mammoth Cave Terrain Centerpiece
Ludstuff has a nice photo essay on buillding a large cave terrain centerpiece. Inspiring.