It works great!
1) Print a voucher from the internet (I think Park City website has a link). Each skier needs a voucher. They will ask for some flight info and an email address.
2) They will send a confirmation email.
3) Save and show your boarding pass and voucher at the ticket window. (The boarding pass that shows you landing in SLC on the same day as you are skiing.)
4) You will also need your ID at the ticket window.
We have used it last year and this year. Very easy, No hassles. Park City, Canyons, or Deer Valley would honor it last year. This year we went to Park City. Note that there may be a couple black out dates.