If you try to run FreeMind on Mountain Lion you get this “nice” error message:

“FreeMind.app” is damaged and can’t be opened. You should move it to the Trash.

To persuade FreeMind to run anyway you can type this command into your console:

java -jar /Applications/FreeMind.app/Contents/Resources/Java/lib/freemind.jar

I read on the internet that you can disable GateKeeper as well to run FreeMind but I didn’t try it.