enable promisc. mode on netwrok cards?

[toisanji]

I am trying to use a program that requires read acces to /dev/bpf* . Is this the same thing as enableing promiscuous mode? If so how can I enable promiscuous mode for en0 and en1? The program I am using said that I could just do "chmod 777 /dev/bpf*", but I would rather do is using a programmed way.
One more question, when I su to root and then run "open /Application/An_Application" how come the program is still run as my non-root user and how can I make it so the program is run in root mode(Which I do require)?
Thank for listening.