which tut. would I want to run things like wireshark, driftnet, dsniff, urlsnarf etc

Can I do this "live" meaning not having to capture to a file first? and which tut would be good for dooing this any-way possible.

to rephrase, can i sniff traffic with out joining a network? and lets say I do join a network and ettercap and wireshark i can see traffic just fine. how would i go about reversing cookies to gain data stored in clear text (port 80)