[X-Unix] How to monitor inbound/outbound network traffic?

[dm87 at proparallax.com]

>Right now, I'm watching the light (xfer) on my network card and it's 
>lit up almost solid, like I was downloading/uploading something, 
>something (data) is going in or out.  I want to know what it is?  
>Which application is sending it and what its sending.  I don't have 
>anything running right now that should be constantly transferring 
>data like this.  Its as if someone is sucking data off of my 
>computer.  Is there a program/app/utility/script that will allow me 
>to find out what is going on?
>
>Rad...

I am using a combination of Little Snitch <http://www.obdev.at> and
Who's There <https://ssl.opendoor.com/orders/whosthereXOrder.html>.

It is truly amazing how many email messages and programs phone home. 
It is also amazing the number of knocks on the door, on a wide 
variety of ports.

Donna dm87