98 Malibu wiring for stereo??

Is there anywhere i can find the wire colour codes for the plug that plugs into the factory stereo ..i am pissed cause the original owner who that was entered a loc code and i have tried for days with no luck to unlock it !!!..Keep getting the Inop message if i dont get it right after 3 trys ?..So i am ditching it for an MP3 player soon and would like to know what wire is what ...eg..power ground and speaker wire ..If anyone has a link to a wiring diagram that would be muchly appreciated .. Thanks