I've decided to take an indefinite break from developing MCEdit. I cannot say whether I'll come back to this project in the future, because the future is perilously uncertain. In the meantime, I've shared the source code on github, and TkTech has volunteered to take up the maintenance role. He'll be the one who uploads the official builds to the Downloads page on github, and who handles any pull requests and bug reports in my absence.
Apologies for the "Ransom" scare. The source code was released free of charge with no payment demanded. A big thanks to everyone who donated regardless. As a gesture of thanks, the last change I made after releasing the source code was partial support for Minecraft 1.2 (Anvil) worlds.
Only unstable builds are available at the moment - use at your own risk.