But the compression used on Skype and video varies the number of bytes per second depending on silence or movements in the video frame. As such no one can tell you an exact answer.
Look to net monitoring features in your OS to measure a session. Here's a command line for XP to see the byte count.
Bytes 4729122 1277866
As you can see, you can answer this yourself.
I have just started using Skype.I have a 2GBs a month limit on my broadband.Can someone tell what a 10mins PC to PC talk or a 15mins Video link would have on my download limits.I don't want to be chatting away and find i have used all my broadband allocation for the month.Thank You.Millreef.