Sorry, Tina, my bad. I know the board guidelines frown upon abbreviations, and for good reason. Some of my collector friends and I have gotten used to using country abbreviations, and it's a hard habit to break. There are many, but here is an abridged list of some commonly used ones (US, you know

)
AAT -- Australian Antarctic Territory
BIOT -- British Indian Ocean Territory
DDR -- German Democratic Republic (East Germany)
DPRK -- Democratic People's Republic of Korea (North Korea)
FSAT -- French Southern and Antarctic Territories
GB -- Great Britain
HK -- Hong Kong
IOM -- Isle of Man
KUT -- Kenya, Uganda, and Tanzania
NZ -- New Zealand
PNG -- Papua New Guinea
PRC -- People's Republic of China
ROC -- Republic of China
ROK -- Republic of Korea (South Korea)
UAE -- United Arab Emirates
UAR -- United Arab Republic (Egypt, Syria)
UK -- United Kingdom
USSR -- Russia
Anyway, these are the ones you will commonly see used in stamp listings. This is off the top of my head, so I'm sure there are a few other common country abbreviations not included.

khj (also an abbreviation

)
[EDIT: removed Libya from UAR list (thanks, Mike!)]