The easiest way to do this in windows is with arpspoof is Cain and able . You scan the network for hosts and use arp poisoning between the Target host and the router. Pretty easy to capture cookies with wireshark
And use his session on say Facebook
Sent from my Desire HD
Unless you know your stuff, rather use Colasoft. Its a "free" download and will pretty much give you everything you need in a graphical interface that is so much easier to understand