A demo of technologies used in MCEdit 2.0 is available for download from the links to the left.
Note that this is a very early version of the software. There are bugs everywhere and most of the important features are missing. Do not use this version for any serious work. Don't bother reporting any bugs either, I already know about them. (Actually, you can report if the app doesn't even open, as long as you attach your
mcedit.log file in a pastebin or something)