Network usage program

[deigima]

Im looking for a program that can detect and show which processes are using how much of my internet. ive lately been getting horrible lag spikes where my internet freezes up and ping goes through the roof and i suspect theres a process nomming on unnessasary connection. i try closing steam skype firefox ect (thats if im not browsing) but the lag spike continues. i could whine to my isp but that wont get anything good, since the lock in contract expired, they refuse to offer support past telling me their network is shit and my modem could possibly need replacing.
i want to atleast try to identify processes using unneeded bandwidth before i go replacing things.

 

[Snortan]

Resource Monitor which comes with windows or Process Monitor http://technet.microsoft.com/en-gb/sysinternals/bb896645.aspx