Very cool program - Let's you explore all kinds of secret and under development areas without private servers, hacks, or questionable use of game mechanics.
Uncheck the "Use Patch" box to make the program load instantly (or without the 3-5 minute delay anyway). Honestly, I have no idea what the Blizzard patches do, seeing as how a patched game should already have the latest files. Perhaps it lets you use the program with just a patch and not the full game, but I haven't tested that so it remains just a theory.
In any case, it makes booting the program up a lot faster.
(Tested on 2.0Ghz MacBook Pro w/ 2GB RAM)