Need to run multiple threads, one thread need to monitor all these

Question

Hi All,
                   I need to develop an application which should use multithreading concept. I need run the multiple threads. And I need to have the one monitoring thread which should monitor all these threads, and make these threads sleep/kill if there is nothing to process in the perticualr thread. And it also create the new threads if any thing comes new to process. This application should run in 24/7 time. So need to make sleep/kill unused threads.
          This all need to work in background as a servic. This sholud be developed using C#. Please let me know which type of application full fills my requirement. And also help me in creating the monitoring thread here.
        This is required to send an SMS to the mobile so that no message should be loss. while implementing this threading.

 
Thanks in advance