To get into that site surley he just logged in as the admin. just type admin in the address bar after the link.
You must login or register to view this content. Then all you need is a password and username username is probally Admin or Administrator and then you could try using and sql comman and get in but im no hacker i know of this stuff but cannot do any of it to save my life. BTW did the guy that hack it leave his actual name there or is that one he made up because you would have to be ****ing retarder to leave your name on a site you hacked.
BTW don't forget to +Rep and thank if i helped you.