Pretty sure it was USA vs Switzerland at the Silverdome, because of all the noise about it being the first indoor game in Finals history.
I trust that you're probably correct. Maybe there was another game played simultaneously in Chicago. That Diana Ross missed penalty at the opening ceremony was definitely outdoor (I think).
Update: The opening ceremony & the first two matches of the tournament were held on 17th June. The first game to be played in Pontiac was USA v Switzerland, a day later.
To round up the answers:
Stadium - Location
Giants Stadium - East Rutherford, NJ (near New York, NY)
MUSIC4EVER - Liquid (MUSIC4EVER)
Rose Bowl - Pasadena, CA (near Los Angeles, CA)
C-ZETA - C-ZETA
Pontiac Silverdome - Pontiac, MI (near Detroit, MI)
Famine - (C-ZETA)
Soldier Field - Chicago, IL
C-ZETA - C-ZETA
Cotton Bowl - Dallas, TX
Liquid - C-ZETA
Robert F. Kennedy Memorial Stadium - Washington D.C.
Famine - C-ZETA
Stanford Stadium - Stanford, CA (near San Francisco, CA)
Akmuq - Akmuq (C-ZETA)
Citrus Bowl - Orlando, FL
Akmuq - Barra333
Foxboro Stadium - Foxborough, MA (near Boston,MA)
Akmuq - Akmuq
If there are any errors, do let me know.