spanning threads in asynchronous call

Hi,
Here is my problem.

I am calling a web service asynchronously as follows

Registred the event handler as follows

_Data.GetDataCompleted += new MyNameSpace.GetDataCompleted
EventHandler(GetControlDataCompleted);
//Here is the call back method
void GetControlDataCompleted(object sender, GetDataCompletedEventArgs e)

{

//I get the some data from eventagrs e.

}

I want to span thread here to do some operation on the the result data and
then fill up some object. As this asyn call is on different thread ann even
if we span no of threadd, they will not executed as the calling async
thread's life cycles ends.

Please suggest me on how to go about it.

This is just to improve the preformance of the WS call as it involved lots
of operation to do on the result.

Thanls alot for your time
~Mohan