rcgreen I actually did purchase the EN104 and despite it being advertised as a hub it does require power and in fact is a switch just one that does not have many ports. I have also glanced at Ebay and the few things that are advertised as a hub look more like a switch to me.
I am sorry that I did not phrase my original post properly. I don't need to create more collision domains and further segment my network I need to maintain the existing collision domains while attaching additional interfaces for the purpose of packet sniffing. The reason why I would like to do this is that I am configuring my own firewall and the ability to packet sniff on either side of the firewall would be nice for further analysis of the network traffic when playing around with the different configurations. I need to become more proficient with Ethereal and the best way of doing this in my mind is to have a practical application.
I was talking to an uncle of mine who may have a hub laying around his place. If so that will be one down now only one to go.