Matt Lloyd offers a set of Basic Skirmish rules with dungeon crawl adventures in mind.
dungeon crawl
Cavern Crawl Dungeon Miniatures Game
Cavern Crawl is a game of dungeon adventure with miniatures.
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.
Pocket Dungeon Game
Pocket Dungeon is a small, solo dungeon game that uses the pocketmod small booklet printing system.
Dungeoneer Dungeon Bashing Rules
Dungeoneer is a set of free wargames rules for an evening of dungeon bashing fun. The author writes:
These are a set of very simple dungeon-bashing rules for youngsters and the young at heart. This is classic kick-in-the-door, kill the monsters and steal their treasure stuff. One player is the Overfiend. He creates the layout of his dungeon, populates it with monsters and treasure and then runs the game. The other players, best between three and five, must guide their Dungeoneers through the dungeon hopefully to emerge victorious, alive and laden down with treasure at the end. Obviously it would be easy for the Overfiend to kill the Dungeoneers very quickly, just by placing a dragon behind every door. This is not his objective however. His job is to provide a fun evening that challenges the Dungeoneers, but may yet kill the occasional foolish or unlucky one.
Dungeoneer is about having a good laugh with your friends. If you play often then each player who wants to can have a turn as the Overfiend. This keeps things fresh and allows the regular Overfiend the chance to kick some monster ass.