Daughter dropped iPod nano and broke the glass. after calling Apple ($79 + tax and shipping), and checking other repair options, I decided to use ifixit to order the parts and used their great online information to give it a shot.
Repair took approximately 5 minutes. Most of the time spent pulling off the borken shards of glass. I did not need to disassemble the ipod to fixit. Take special care to remove all the debris and adhesive from the unit prior to placing the new. The only concern that popped up was the absence of information on how to prep the new glass, what to remove from the glass, what to leave etc. But if you take you time, it's turns out to be pretty fool proof and worked very well.
The glass comes with scratch protection sheet on the outfacing side. The side of the glass that goes towards the unit has backing to protect the adhesive and a full face adhesive sheet. Remove both one at a time. The pertinent part of the adhesive will remain around the outer edge of the glass.