You can use TWA, Continental, and Northwest lounges when you are flying them. There are also several non airline lounges you can use anytime:
Consul Club Lounge, Frankfurt, Germany
Grand Daube Lounge, Vienna, Austria
Salon Centurion, Buenos Aires, Argentina
Centurion Elite, Mexico City, Mexico
First Class Lounge, Abu Dhabi, UAE
First Class Lounge, Dubai, UAE
Delmon Lounge, Bahrain
Oasis Lounge, Jeddah, Saudi Arabia
Cedars Lounge, Beirut, Lebanon
As for the International Airline Program the participating airlines and their destinations are:
Aer Lingus - Ireland (Premiere)
Aerolineas Argentinas - Buenos Aires and South America (Club Gold)
AeroMexico - Mexico (Clase Premier)
Air France - France, Europe, Middle East, Africa and Far East (Concorde and First Class) 1/1-4/30/00 Only
Air New Zealand - Australia, Europe, New Zealand & Pacific Islands† (First Class, Business Class)
† Pacific Islands offers only Business Class
Alitalia - Africa, Europe, and Middle East (Magnifica Class)
Asiana Airlines - Asia (Sleeper First Class, Premium Business Class)
Cathay Pacific - Hong Kong (Business Class) 9/1-12/31/99 Only
Continental - Birmingham, Glasgow (effective 7/15/98), Lisbon, London Manchester, Paris, Rio de Janeiro, and São Paulo (BusinessFirst)
EL AL - Israel Tel Aviv (First and Business Class) 5/1-12/31/99 Only
Iberia - Africa, Central America, Europe, Middle East, and South America (Grand Class, Business Class)
LanChile - Chile, Peru, and South America (Premium Class, Business Class)
Lufthansa - Europe, Middle East, Africa, and Far East (Business Class)
Malaysia - Malaysia, Southeast Asia, Middle East and Australia (First and Golden Club)
SAS - Europe, the Baltics, and Scandinavia (EuroClass)
Swissair Africa, Europe, Far East and Middle East (Business Class) 5/1-8/31/99 Only