For their Mars Attacks game, Mantic released sets of 20th century style brick ruins. They’re good looking, but with a little work can be even better.
The Miniature Wargaming Editor
Kings Of The Ring Fighting Game
Kings of the Ring is a set of free wargames rules for one-on-one combats.
Making Hedges With Plasticard and Clump Foliage
Here’s another tutorial on making hedges — useful for lots of different settings.
Making Ruined Roads from Vinyl/Lino Tiles
The Tabletop Terrain blog has a useful article on using vinyl/linoleum tiles to make roads appropriate for a combat zone or post-apocalypse setting.