I know if you are making your own cd's from Cd-r's you just make a cd that has audio and data on it. Don't know how it works if you are getting them duplicated
I can also provide this service if interested. More than the creation of the disc, the real talent lies in the creation of a user interface for the "extra" portion, video editing, and content mastering.
I've seen some of my cd's with it and they have a flash infrence kinda thing for the goodies. You could create that in Macromedia's flash program but if you expect to just get it and start off you can get lost. Maybe create some type of pogram to do it. I don't really know. Then make an iso(a cd image) of all the files and burn them in something like nero w/ their cd and data option or something. I never tried it tho. Just thought about it. With the audio and data thing in nero you can add your albums cover and back images which is prety cool into the file. I've heard it makes the 1st track when u play in a cd player the data and messes up. I guess I ought to try this out and see how it goes.
In nero you can specify it to be the last track i believe, but for some reason I think that I have done it to where the one track doesn't play in a cd player. I have only made an enhanced cd once or twice so I cannot remember correctly
It seems like the newer CD players ignore the data files. I remember when those CDs first came out you would get that ear wrenching digital noise but I don't recall hearing it in a long time.