To work it, login using your EndGamer forum account, click on the "Cracker" tab, and load up a username and password list. Click start and wait for the program to finish. Should there be any cracked accounts, a text file will be created in the cracker's root folder with the cracked information. This text file is never overwritten, so all new entries will be added to the file (until the file is moved or deleted).
To get users, click on the "username leecher" tab. I got kind of lazy when coding this, so so far it only supports sucking usernames from single forum threads at a time, but should this cracker become more popular I'll add an automatic leecher. To use the leecher, find an address of a thread on the official minecraft forums ( http://www.minecraftforum.net/index.php) and put it in the text box. Click the grab button, and you'll have the list. The list updates itself and deletes doubles so you can put in as many threads as you like into a single list. Click export to save the file (this file can then be used as a username list for the cracker).