Need recommendations for sniffers

I am in need of a free network packet capturing tool that can do the following:
--Allow me to sit at my desk and capture traffic from another machine on the network including different subnets
--Charting the traffic would be nice
--Allow me to capture traffic according to protocol, http, etc.
--Resolve ip addresses to netbios names
--Has instructions/guide that is easy for someone who is not a veteran network expert

I am a linux/unix beginner but I am willing to look at a linux/unix solution although I have had trouble deciphering some of  the documentation from sourceforge.  

I perfer free but will look at commercial.  Right now I am looking at Ethereal and reading about it.  Our clients are windows 2k and win XP, servers win2k and 2003.

Thanks for any recommendations;

MaureenStart Free Trial