PNetMon displays all local and remote network activity involving your PC, allowing you to spot suspicious activity.
PNetMon consists of two components - a service that runs in the background collecting your PC's network activity and a client program that you run whenever you want to see activity. This design serves two purposes - first, it eliminates the need for the client program to have Admin privileges, and second, it allows PNetMon to maintain a running list of recent activity even if you forget to run the client program. When you start the PNetMon client program, you'll see all network activity that has occurred over the recent past. You can also now set the client program to auto-start at Windows boot-up.
PNetMon is small and easy to use. Installation, plus .Net is required. Tabs include Program, Filter, Refresh, Appearance, Unsort, and Clear.