The Repository is a website intended to help people to hack ROMs in the comfort of their own homes. The site is a repository (hence name) of documents, utilities, advice, tools all aimed at allowing people to change the graphics, scipt, levels, palettes, or code of video games.
There is also a large and helpful message board which is frequented by many accomplished hackers, such as Gideon Zhi (his username is Lakmir, just like his name on IRC, but it's him...), Klarth (author and developer of Atlas, the best script insertion utility currently available), Shadowsithe (who has released translations for the Megami Tensei Game Boy games), Spinner 8 of The Whirlpool and many more. If you have a question about ROM hacking, no matter what your level, there is a reasonable chance that someone will be able to point you in the right direction, or at least to a relevant document which tells you how.
The site has had a.. well, turbulent history, after moving hosts and changing names a good few times. The site was founded under the name Romhacking dot com, in August 2000 or there abouts, to provide both a place to find utilities and docs, but also to provide an alternative to hosting from Emulation World. After numerous problems, such as free hosts shutting down and parodius.com not having them due to "exorbitant bandwidth costs" , the site eventually had to swallow it's pride and move to Emulation World to be hosted there for a while, in September or October of 2002. All these dates are a little sketchy, but they are taken from the "About the site" page, so it's InVerse's fault, not mine... However, around the end of 2002, the site moved back to the original domain name (www.romhacking.com) and has remained there since, although it has changed name to "The Repository". The site was run by InVerse when I first knew it, although he has since relinquished control to a newcomer named Coraline, who made her first news post on June 10, 2003 and appears to be updating frequently since. InVerse is still around, however, occasionally posting news, and he is also working in a new ROM management utility to rival the GoodTools, which he, like many other ROM hackers, has major problems with.
If you're looking for a Document to help you with anything, then if it's been written, it will be at The Repository. Pretty much every Hex Editor, text editor, and graphics editor is there as well. There is an Assembly and Coding section promised, to go with the graphics and text hacking, but it.. err... isn't finished. And it's been like that as long as I can remember. Luckily, I am nowhere near good enough at hacking to be worrying about ASM.. Still, Coraline looks as if she is updating the site more often than InVerse, so hopefully we will see some ASM tutorials soon. In the meantime, it's pretty much guaranteed that someone who reads the forums can help..
Special final mention must go to InVerse's April Fools joke this year (2003). I first logged into the site a day after April Fools Day, to be greeted with a blank page, and "This site has closed down due to complete lack of support." I assumed it was a joke he'd forgot to change, and went away. Next day, I log in again, to find the same message, appended with a suggestion as to a chatroom where people could direct further ROM hacking questions. I naturally assumed that it was serious, and went away, slightly upset, to try to find some other place to learn to ROM hack. However, ages later, I was msged by yerricde to tell me that Romhacking.com was back. InVerse's news post, dated April 4th, simply said "Told you I was hardcore...". Bastard.
Too much time hanging around on places like The Pantheon (Aeon Genesis message board), forums.cherryroms.com, and the Repository message board.