With the method I was referring to there is a collection of songs. Its in the scorehero.com forums under software->custom songs. If you have an account here is a
link
The whole process is not too difficult and basically involves transferring the game files to your pc, replacing the existing songs with note schemes from the database, then creating a new game disc which can be read by a modded ps2.
Don't ask me for details of the process since I just relay what I know from a friend. I'm sure you can find the entire method with some searching.