I just found this thread after trying to compile a list of my own from lots of different sources. I don't think that there really exists a *definitive* list as these seem to vary by the FAA, by different airlines, by different travel agents, etc. This is the most thorough list that I have, but I've pretty much given up on having a perfect list, though corrections or additions were certainly still be appreciated...
(Note that where there's a *, the metro code can represent either a metro or a specific airport. Argh!)
BER - Berlin, Germany - SXF, THF, TXL
BHZ - Belo Horizonte, Brazil - CNF
BUE - Buenos Aires, Argentina - AEP, EZE
BGT - Baghdad, Iraq - SDA
BUH - Bucharest, Romania - OTP
CHI - Chicago, IL - CGX, MDW, ORD
DFW - Dallas, TX - DAL, DFW or DFW *
DTT - Detroit, MI - DET, DTW
GLA - Glasgow, Scotland - GLA, PIK or GLA *
HOU - Houston, TX - EFD, HOU, IAH or HOU *
JKT - Jakarta, Indonesia - CGK
KCK - Kansas City, KS - MCI
LON - London, England - LCY, LGW, LHR, LTN, STN
MFW - Miami, Ft. Lauderdale and West Palm Beach, FL - MIA, FLL, PBI
MIL - Milan, Italy - LIN, MXP
MMA - Malmo, Sweden - HMA, MMX
MOW - Moscow, Russia - BKA, DME, SVO, VKO
NRW - Nordrhein-Westfalen, Germany - CGN, DTM, DUS, FMO, MGL, PAD
NYC - New York, NY - EWR, HPN, ISP, JFK, LGA, SWF
ORL - Orlando, FL - MCO, ORL, SFB or ORL *
OSA - Osaka, Japan - ITM, KIX
OSL - Oslo, Norway - FBU, OSL, TRF or OSL *
PAR - Paris, France - CDG, ORY
QBZ - Belize City, Belize - BZE, TZA
QDF - Dallas, TX - DAL, DFW
QDV - Denver, CO - DEN
QHO - Houston, TX - EFD, HOU, IAH
QKK - Maui, HI - OGG, JHM
QLA - Los Angeles, CA - BUR, LAX, LGB, ONT, OXR, SNA
QMI - Miami, FL - MIA, FLL, PBI
QNK - Kingston, Jamaica - KIN, KTP
QSF - San Franciso, CA - OAK, SFO, SJC
RIO - Rio de Janeiro, Brazil - GIG, SDU
ROM - Rome, Italy - CIA, FCO
SAO - Sao Paulo, Brazil - CGH, GRU, VCP
SDZ - Shetland Islands, Scotland - LSI, LWK, SCS, UNT, WHS
SEL - Seoul, Korea - GMP, ICN, SEL or SEL *
SHA - Shanghai, China - PVG, SHA or SHA *
STO - Stockholm, Sweden - ARN, BMA
TYO - Tokyo, Japan - HND, NRT
WAS - Washington, DC - BWI, DCA, IAD
YEA - Edmonton, Canada - YEG, YXD
YMQ - Montreal, Canada - YMX, YUL
YTO - Toronto, Canada - YKZ, YTZ, YYZ