promiscuous packet sniffing

i'm pretty new to the world of packet sniffing and would liike to know the possiblities to moniter in and out going packets from a remote IP address. If any one could shed the some light on if this is possible or not it would be appreciated.

Easily with Ethereal (Which has since changed it's name), just set up a filter to monitor only one IP Address, granted you're on the same network as the other user.

ya, not on the same network