Log into a switch and ping the host's IP address, this logs the mac-address in the switches MAC table.
Run the command 'show ip arp 192.168.0.1' replacing 192.168.0.1 with the host's IP address.
This tells us the host's MAC address. To resolve this layer two address to a layer one "address" (i.e. port number), we need to query the MAC table.
Run the command 'show mac address-table address xxxx.xxxx.xxxx' replacing the x's with the MAC address resolved from the previous command.
This command will show us 1 of 2 things. The first is the port the host is plugged into. The second is the port of the next switch the host could be plugged into. If the host is on another switch, telnet to the next switch and repeat the instructions from the beginning.