From StarWars.com:
"For the third part of our Celebration I audio coverage from Hall A of Denver's Wings Over The Rockies Air and Space Museum, Episode I concept artist Iain McCaig shares the stage with costume designer Trisha Biggar. Together, they discuss the designs and construction of the various costumes seen throughout The Phantom Menace..."

Part 1
Part 2


See also
A Look Back At Star Wars Celebration I: Party Like It's 1999
A Look Back At Star Wars Celebration I: Steve Sansweet & Nick Dudman Audioclip
A Look Back At Star Wars Celebration I: Jar Jar Jam