leffel

Hi everybody, Im not sure whether this title fits but I am looking for a special kind of site navigation. At the moment I am using something like: /URL/?site=test to navigate to the subsite "test" .. however, what I would like to use is: /URL/test/ to get to to the "test" site.. What I have thought of so far is to make php automatically create subfolders with index files and preset vars so the specific content will be loaded .. However, this would totally increase the storage and traffic used I think. Does anyone know of a more suitable version or what something like this navigation is called? thanks in advance