You can burn a DATA CDR of your mixes. Do so with aiff files instead of .wav (PC's can read both, but Mac's need a special converter to read .wav's, and that is just an extra bit of time you will spend at the mastering house...so aiff files are best really....). Burning a DATA CDR means the mastering house can use your aiff files of the stereo mixes in a number of ways, and you will still retain your 24 bit. If at all possible, DO NOT take an Audio CDR you burned at home to them for mastering. If the mastering house cannot work with 24 bit aiff files, you should not be paying them for work!
A couple of other things. DO NOT apply your own fade out to the overall mix. If you want a fade out, let the mastering house do that for you. You will be there for the session, so you can tell them exactly what you want and hear it.
DO take along some CD's that you are very familiar with the sound of with you. You are going to want to hear how these CD's sound in their room so you can make better decisions about what your stuff sounds like after mastering and make any corrections before you are done. It would also be a good idea to take along a couple of CD's of stuff you consider to be "LIKE" your production. This will give you and the engineer a sort of "standard" to try to achieve.
Remember, loud is not always good! Look to improve the overall sonic quality of your recording at mastering, not to just make it as loud as possible. Don't let the mastering engineer convince you that you have to compress/limit your mixes any more than you feel is good for it. I have heard too many "professional" mastering jobs that compressed the hell out of stuff to the point of distortion in the mixes, and basically, ruined to overall sonic characteristics of the sound the recording had in doing so. If you remember that what you are hearing with your mixes is very close to what it will sound like after mastering, you will be more apt to be a bit more gentle in compression/limiting.
Have fun and good luck.
Ed
