implementation for Show me as "Away" when I am inactive for "x" minutes

Question

Hi, Does anybody has any idea how to give implementation in c-sharp, of the following feature of Yahoo or MSN: Show me as "Away" when I am inactive for 10 minutes. I have a chat client application developed in c-sharp. And now I want to give the same feature in my app too. Prompt reply will be appreciated. Regards, Kamran