You can now track (some) TTC streetcars online at NextBus. The service also includes a live map of the cars (like the one you can see at Spadina station), and a text service where you give the stop and a time limit, and it'll text you when the car is that many minutes away. It's GPS based, so it should be accurate even when the cars are not on schedule.
The streetcars with the worst service (Queen) are not on the service yet, but St. Clair, Bathurst, College and Dundas all are.
someone must have noticed a big hit in use; most of the routes have been pulled.