The Mini Stories blog has a nice photo tutorial on making snow bases.
Scratch Built Machine Gun Nest
Here’s a photo essay on building a 15mm machine gun nest.
Dungeon Tiles To Print and Play
Quests of Legend has a nice collection of dungeon tiles for you to print out and use for your role playing or miniatures games (or both!) in a dungeon crawl.
Making 15mm Vegetable Crop Fields
Big Lee’s Miniature Adventures has an illustrated tutorial on making model 15mm vegetable fields from corded dormats.