And the new version (currently under development at http://www.canalplan.eu ) allows you to add new places on the fly. For example this morning I added 5 places on the River Weaver and now any routes planned on the Weaver, by anyone using the site, take those places into consideration. The same "immediately available" feature applies to photos too. Add it to a place and its just there.
Nick is also adding more "user input" style features and if there is something you think you'd like it to do that it doesn't, within reason of course, then you can always raise them through the google project page at http://code.google.com/p/canalplanac9/
Of course being web based means that you can even using it from web enabled phones (such as the G1).
Yes, I do have a vested interest - he's my brother and we've been working on parts of the new site together, and original idea was mine ... rather a long time ago!
Steve