I learned how to use the PDA version of CO.com to see the upgrade list. But now a lot of flights I book are UA metal, even if booked on CO.com.

How does one do the same for UA flights?

The CO site sends you to UA to check in with UA conf #.

I tried going to UA on my iPhone (on a United flight they said you could use that to chekc upgrades) but I could not find any option to see the upgrade list.