I started to code the sewers generator. Depending on the city size, there can be several underground levels. The first one will be relatively clean with corridors running under each street of the city, but the deeper you go, the more it turns into caves with twisted galleries and hidden passages. It may even be sometimes connected to a bigger and more difficult dungeon, like a troll mine or a goblin underground city...
I also added an article to the website about a simple dungeon generation algorithm :
http://jice.nospam.googlepages.com/basicdungeongeneration
