[GadgetKen]

Used to go to Toronto 2x a year on business with a Fido sim chip. Prepaid data rate add-ons are now:
Regular phone: $1 day/$3 week/$10 month. All you can eat on the theory a regular mobile phone won't inhale too much data.
Smartphone: $2 day for 20 mb/$7 week for 125 mb/$25 month for 500 mb.
Blackberry: $20 per month.

Otherwise it's a per kilobyte charge and/or per item charge to download stuff from the Fido portal. Caution on Fido is you will have to set up the browser settings on your phone (instructions can be googled on the web or I can post what I used for a moto razr). Or see if your lodgings have a free internet cafe (some limit the time you can be online to be fair to other guests).

Other options are to bring a small laptop (or a wifi capable device) and hope for free or cheap ethernet or wifi, dial-up ISP if you have free local calls at your lodgings (Juno has Canadian dial-ups), or get a prepaid data stick (Virgin Mobile Canada running I think on Bell Canada).