The Cambodian Air force's retired fleet of MiG21's at Pochentong Air Base are at:
11°32'50.83"N, 104°51'8.39"E or 11 32.800N, 104 51.139E
Also viewable are the old helicopters used during the war with Vietnam.
If you look closely, you can see the two MiGs which are still in service, in the small hangar.
I work at Air Traffic Control, so was able to get access to film these planes (poor quality Nokia N73 video).
the video is at:
http://www.youtube.com/watch?v=piFmRz524C4