Searching around has revealed neither a trick, nor an app that will automate the process of using a calling card / access number when dialing long distance.
Did I miss it?
I'm surprised there isn't more interest in this.
specifically, I'm looking to an app to help insert XXXACESSNUMBERXXX pause XXXCALLINGCARDNUMBERXXX pause XXXFINALDESTINATIONNUMBERXXX
(where final destination number is chosen from the contacts list)