Does any one know about a software to monitor network activity. I want to keep a check on the softwares installed, that to which sites they are making connections.

I have noticed that a lot of network activity keeps on going through my machine. I want to check it.

I have an app, called NetWorx, which has a netstat option to display my softwares network usage and connections, you can try it (google it up)

You could always run a monitoring/analysis program such as WireShark that gives you all of the network traffic packets moving across your connection, along with application details such as transfer protocol used, even sometimes as much as data sent.