I have a web app and I want to see how much traffic it can take without crashing.
Is there a service or a product out there that will pound on my web site with thousands or tens of thousands of hits for a sustained period from a variety of geographic regions?
One option I have read about is to use Amazons EC2 to generate the traffic, this means you can rent a large number of machines from a few different geography's for relatively little money. You can then run up existing load testing tools as the other answers are mentioning or write your own if you have special requirements.