Here's a list of places you can access the internet, some free, some not... please feel free to added to the list.

FON - Not quite free, but close enough
Hotspot Found in many coffee shops e.g. Second Cup. It does cost money to access the Hotspot network.

The city of Mississauga offers free WiFi access to the internet at the libraries, community centres and other facilities listed below (You need a valid library card to access the net)

Community Centres

Other Facilities