Manisha,
Wht exactly is ur requirement? Do you want to calculate how much data is transferred in 1 hr of Video/Audio Chat or do you want to know in advance. If you want to calculate it then you can use the Network Neighbourhood icon in the task bar. Pointing the mouse cursor on that icon will tell you the amt of bytes sent and received. If you want to know in advance then you can try doing a Video Chat for 10 mins, calculate the amt of data sent and received and multiply each by 6 to get an approx value of amt of data transffered.
HTH,
Marooned
