"There are two types of websites out there: cottage rental agencies (e.g. Red Stone rentals, WRD Cottages) and websites that just provide listing services. The best one is FindCottage.ca since it has great interface and many cottages. You can also try homeaway.com (not too many ontario listings) or clrm.ca (interface is not that great).
In Ontario during summer it is advised to search for full weeks rentals and most of them are rented from Saturday to Saturday.
Hope this helps."
