How do you put music in gta vice city game?

Dude I have no idea why you didn't ask on our site, but unless you modded your PS2, which is illegal, you can't. There is a huge process into modding your PS2, and since it is illegal I'm not going to go into it here, but check google. After you did that you need to convert our files (which you can find on modded PS2 sites).

Good luck.