The Us flag code is clear on this issue for display/ wearing of the U.S.Flag.
most of the flag hooplah post 9-11 Was a clear violation of the code.
These links may provide some guidance. As far as other countries flags it still is Insulting to see the flag as clothing. type the U.S. Flag code and you will get lots of information.

http://www.bcpl.net/~etowner/flagcode.html

http://www.legion.org/?section=our_f...tent=flag_code