the site is fine and safe. There was report of the site showing suspicious script at one time for some reason and was down for a moment. They are still getting the database and downloads back up.
Back online May.07.2011
posted by: Pineconn
It appears that this website is no longer running suspicious scripts and that you can access the quests. Unfortunately, it looks like the FAQs and Downloads pages were wiped, as well as the tilesets for quests were reset.
Let us know if you find any additional problems on the forums or as a comment to this news post.
EDIT 5/15: It appears that the Downloads page is working again. However, I found that the comments for each quest have also been deleted.
I used to fiddle with ZC myself for a while but never made a full fledged quest. Never got passed making a custom tile set with Link's Awakening sprites in nes color palette which is unfortunately lost now.
Here is another link to a forum for Zelda Classic
http://www.purezc.com/As far as something similar for roguelikes, I remember there being a roguelike creation program in dev that looks similar to zzt. Unfortunately I don't have a link but I think it's here in the forums somewhere. It's not complete though.