I have sent a private email to Iain but thought I would try to help others in locating and identifying Sparrows. If you have contrary views then keep in mind that the following is my way of finding and identifying Sparrows but it may not be your way.
One of the most important tools I have found and I use all the time is voice or song recognition. I have over the years learned to identify Sparrows from their songs and to a lesser extent by their chips and also a lot of the times if I do not recognize a song or chip I am fortunate to be with someone who does know. I do not profess to know it all but I must again stress "Learn the Songs and Chips".
Good Software are Thayer Guide to Birds of North America by Cornell Lab of Ornithology, available on line. Petersons Guide to Bird Songs on CD or Tape and the Stokes Field Guides to Bird Songs on Cd. All of these can be transfered to an iPod (which I have done) so you can listen to them if you are standing in front of a Sparrow you do not recognize. You could also type in Sparrows of Ontario or Canada or North America on the internet and find a zillion identifying sites for individual species.
There are of course several good Field Guides like The Sparrows of the United States and Canada by James rising and David Beattle (a Toronto Birder) , Sibley Guide to the Birds, and National Geographic Guides to the birds All available at the Outdoor Bookstore on Victoria St. at Adelaide in Toronto.
I do not know exactly what you are after but above is an attemp to help. If it is a particular species then let me know as I have a million books, etc. It is getting late in the season for a lot of song but the fall migration will soon start and a couple of the best places in Toronto I have found are the Toronto Islands, especially around the airport (Sharp-tailed, Le Conte's, Grasshoperr , Vesper, Dickcissel have all been seen there by me) lus all the usual suspects including Harris's seen by others, the Leslie St. Spit (Sharp-tailed, Grasshopper, Henslow's, Lark have been seen there by me) plus all the usual suspects. Best times are from mid September to end of passerine migration in late November.