Mac OS X Server Software Support-Select: How to find the enrollment number
If you are trying to enroll or register your recently-purchased Mac OS X Server Software Support-Select, you will need to reference your enrollment (registration) number. (For other types of AppleCare agreements, look here.)
Inside your Mac OS X Server Software Support-Select box or envelope you will find a booklet that says "Getting Started" at the top. Just to the right of these words is a barcode with your Mac OS X Server Software Support-Select enrollment number above the barcode:
Once you have located your registration or enrollment number, you can activate your coverage here.