I'm also from the Toronto area but never had to use a boarding service. I would start by checking with local vets and see what they recommend.

Most people prefer to have a pet sitter come by the house, so that the pet is not stressed from being in a new environment.

Here are two links for a pet sitter in the Toronto area:

Pet Services Toronto

Paws 'R' Us

And here is a pet boarding service located on Spadina:

UmbrellaPets


Just found this website with more links to boarding and pet services:

Toronto Pet Network

Hope this helps!