For anyone adding a state drop-down list to the Custom Registration/Profile Field area, I made this list today and thought if could be useful to others.
US|Choose a State…|default
XX|Outside US and Canada
AL|Alabama
AK|Alaska
AB|Alberta
AS|American Samoa
AZ|Arizona
AR|Arkansas
AA|Armed Forces Americas
AE|Armed Forces Europe
AP|Armed Forces Pacific
BC|British Columbia
CA|California
CO|Colorado
CT|Connecticut
DE|Delaware
DC|District Of Columbia
FL|Florida
GA|Georgia
GU|Guam
HI|Hawaii
ID|Idaho
IL|Illinois
IN|Indiana
IA|Iowa
KS|Kansas
KY|Kentucky
LA|Louisiana
ME|Maine
MB|Manitoba
MD|Maryland
MA|Massachusetts
MI|Michigan
MN|Minnesota
MS|Mississippi
MO|Missouri
MT|Montana
NE|Nebraska
NV|Nevada
NB|New Brunswick
NH|New Hampshire
NJ|New Jersey
NM|New Mexico
NY|New York
NF|Newfoundland
NC|North Carolina
ND|North Dakota
MP|Northern Mariana Is
NT|Northwest Territories
NS|Nova Scotia
NU|Nunavut
OH|Ohio
OK|Oklahoma
ON|Ontario
OR|Oregon
PW|Palau
PA|Pennsylvania
PE|Prince Edward Island
QC|Province du Quebec
PR|Puerto Rico
RI|Rhode Island
SK|Saskatchewan
SC|South Carolina
SD|South Dakota
TN|Tennessee
TX|Texas
UT|Utah
VT|Vermont
VI|Virgin Islands
VA|Virginia
WA|Washington
WV|West Virginia
WI|Wisconsin
WY|Wyoming
YT|Yukon Territory