CurrPorts is another great, free utility from NirSoft. You can download it here.
This utility gives you data on your TCP/IP and UDP ports. The Transmission Control Protocol / Internet Protocol ports show which applications are communicating via the internet. The User Datagram Protocol is an alternate way for applications to communicate over the internet. TCP/IP connections involve the transfer of data in two directions, whereas UDP sends data in just one direction.
CurrPorts will show you the address and name of the hosts your computer is communicating with.