If you want the most recent population counts for Canadian cities and towns, then head to the Census section of the Statistics Canada web site.
Here's the page listing the population of the 33 census metropolitan areas and the 111 census agglomerations as determined in the 2006 census (the values for the 2001 census are also listed). The smallest place on the list contains 8,987 people.
Or, you can start with
this page, which is the first of thirty-six pages listing the 2006 census population counts of all the urban areas in Canada. There are a total of 899 urban areas. The smallest on the list has a population of 1,003.
If that's still not enough, then go to
this page, which is the first of 52 pages listing the 2006 census population count of every designated place in Canada. There are a total of 1,289 designated places.
There are links on all these pages for downloading the data as either comma-separated or tab-separated files.