Unpacking of malware, like Sasser

["Dennis Rand" <der () infowarfare dk>]

Hi there
 
There has not been so much talk as i could find on discovering how to
unpack a malware program like sasser and other viruses and worms,
I were wondering if there are any way of discovering how a malwared
program are packed eg. is it packed with UPX or something like that.
 
Hope you can help me, in the right direction =)
 
Regards
Dennis