Designing your URL's in one of the important principals in my list for enabling web services. Its a good idea in any event. This paper from Port 80 Software discusses some strategies for making URL's useful. Most are pretty good and worth implementing. I don't agree with one however. They advocate disguising the query strings in a GET. I think that is a serious mistake. While it might make a URL easier to remember, it potentially makes the application less generally useful and complicates the API description. A consequence would be that other's who wish to write programs to interface with the GET query would have to write cusomt code to interface with your application. My advice: stick with standards here.