OpenStreetMap is a project to build a free (unencumbered) map of the world, similar in scope to the various commercial web-based maps that you might have used. They're making good progress in some areas and, in fact, the outlines of Toronto are now pretty well fleshed out. Some of the local open source people are having a Toronto mapping weekend centered on the LinuxCaffe and, of course, I'm giving one of the presentations (Saturday at 11). If you're free for even part of the weekend, why not join us?