Do you mean a sitemap that lays out the pages and their associations? If so, I've tried that before... and it's really not that easy. If you choose to do it... I would try it with a UML-like approach. For each core function of the site, create a "Class" and then map all the "Methods" (or actions) and the optional "attributes" for each method. This gives a "high-level" overview of what's actually happening. Then, once you've identified all your "classes" you can do a flowchart of the site, and all the associated pages, and reference the classes within the flowchart.