looking at the network traffic

[Luca Ferrari <fluca1978@virgilio.it>]

Hi,
using program such as ethereal, tcpdump, etc. is it possible to see the 
network traffic also if the hosts are connected thru a switch? I mean, if 
A,B,C, are on the same network, connected with a switch, can A see the 
traffic among B and C? I suppose no, since the switch should route the 
traffic to the right host directly (while an hub should not), and the only 
thing I can see should be message broadcasts and something similar. Is it 
right? Is there a way to observe the traffic over a network even if there are 
switches?
I don't want to break user's privacy, but since I'm developing  a program 
which should connect to a peer-to-peer client, and I don't have protocol 
specifications, I was wondering about a traffic dump of a session among two 
users. Nevertheless I was unable due to (I suppose) the switch.

Thanks,
Luca

-- 
Luca Ferrari,
fluca1978@virgilio.it