I heard it was down for a while then I heard it was back up. I am sure I was about to post that here then saw someones post on here saying that it was back. The person who was doing the most work on it that I could tell was Kepli who is a member here but I have not seen mail for ages. They were also on RPGMapShare and the four ugly monsters site too.
If you give up on them then you can try mine which is somewhat similar - ViewingDale link in sig. Also there is DungeonForge which is a similar and free kind of thing but you have to register on the site to get their link I think. Also fractal mapper is kind of similar in style too. All of those three are 'stamp based' i.e. you stamp down copies of PNG style bitmaps with rotation and scaling. Each, including dundjinni, has pros and cons so check them all out and see what you like from them all. If you want any questions about mine then ask away. RobA knows DungeonForge pretty well I think and Mark Oliva here waves the flag for FM8. You can also check out the popular MapTool which is a VTT with stamp tool kind of map abilities (Trevor, or Torstan here can give some advice on that one) as well as Battlegrounds RPG which Heruca is the dev for and is also a member here.