The Toronto Star has a big map of languages spoken in Toronto, using 2006 census data.
Bricoleururbanism.org, a wonderful blog, has digested some of the map images for you, and here is one:
Makes me think of a good question for schools and universities: why aren’t you guys doing this stuff in your classes and publishing it like crazy? Wouldn’t it be nice if a big chunk of school work was designed to be actually useful to the world, and actually was? And was distributed freely on the net?