1. Outline the class you are going to make a CD for. Each format you teach (step, sculpt, etc.) should have its own outline. Your outline may be comprised completely of radio play formatted songs, or it may include some blocks that will use traditional cardio music.

2. Burn your regular CDs to your hard drive. This will give you a library to start with. Consult some websites for more ideas.

PromoOnly.com - this is a company that distributes current releases to radio stations and DJs. They deal directly with the record companies, so their lists contain all of the music that will be getting air time on the radio during any given month.
Billboard.com - The top songs by category Music station websites - mtv.com, vh1.com, your local radio station website, etc. Always include one or two fun oldies. http://www.digitaldreamdoor.com/pages/music0.html - contains all kinds of ?Greatest' lists.
FitClasses.com - downloadable radio play formatted choreography and workshops

3. Download any new music you may need from Napster.com, Walmart.com, MP3Sugar.com, BurnLounge.com or any others that sell music over the internet.

4. Match objectives from your outline to songs. Make sure that the beats per minute are appropriate for each objective. (MixMeister.com has a free BPM analyzer available for download from their site.) Burn the songs to a CD in the order that you will use them in class.