Ours was in the Kit of Parts, and according to the KoP checklist it was in everyone else's too.
It is a CD-ROM-sized envelope that is prominently marked as containing the 2012 LabVIEW for FRC installation media. If I recall correctly, the background is white and yellow.
Inside the envelope is a business-card-sized USB flash drive (the drive itself is actually very small, and it "flips" out of the card).
The instructions for using it are in the "Getting Started with the 2012 Control System" document on the Kit of Parts web site. In fact, pretty much all of the information you need to use the provided parts can be found there:
http://www.usfirst.org/frc/kitofparts