I noticed töff recommend DungeonCrafter3 in another thread.

I think it ought to be noted that DC3 is a barely functional program that has not been developed since 2007. It has a fixed cell size of 72x72, a maximum map size of 15x15 (developers said it slowed down too much with more complex maps) and cannot save, only export.

DC1 was a perfectly functional program, but limited in terms of cell size and the images it could use. DC2 had improved usability but was never finished and a lot of users used both DC1 and DC2 to work on a single map. DC3 was released when it was in a pre-pre-preAlpha stage, had a very minor bug fix and then nothing. DC1 and DC2 (and tilesets) are available from the DC3 website (Legacy section) and are also available on teh Dungeonforge website.