Thanks for the great advice. Just a few more questions.

1) Is this something I could do all in one swoop? So I could call AA and say I want to go from PHX to LHR and I want to use miles plus cash to upgrade or I won't want to take this flight or will they say you have to buy the flight first then we'll see what happens on the upgrade.

2) I'm suppose to use our corporate travel web site which is the corporate site for Expedia. Could I book there and then turn around and call AA and try to do the upgrade?

Just trying to figure out the best way to do this.

Thanks again.