need help on multi thread pinger

I dont know what to term it so I just titled it multi thread.

Actually I have made this list of site or ip address on a listbox and I was able to ping them one by one through a loop. But this is not what I want to achieve. I dont want a looping style but instead I want to ping all of those in the list with is own thread or instance. I dont really know what proper term. How should I do that?