along with the protocol analyzer (sniffer), you can use something like "iptraf" for linux.

On windows... the utility "cool beans " seems to do it too. (just gives you the traffic in kb) though... not quite as good as "iptraf". It won't break it down to connections....

I can't find a good program for windows that will do what "iptraf" will do...

HDD, you beat me to it.