Outgoing Traffic Monitor/Restrictor?

Greetings!

I am looking for a free PC application that will inform me whenever an application tries to send information across the internet.  Preferably, the application would also give me the option to stop this information from being sent.

I have seen the WinXP McAfee firewall program do something along these lines, but the application isn't free.

If someone could help, or at least suggest where I start looking, I would very thankful!

>>5
Ah yes that well known hardware that can see what programs are running on all computers on your network.