Today in a Vancouver mall, I purchased a Koodo SIM for my iPhone 4S. Koodo uses the Telus 3G network. The SIM+1GB data + 20 minutes voice + (unlimited I think) texts was $56 (Canadian) for one month. Calls to the US count for two minutes per minute of call time. PIN-based vouchers for refills are available at 7-11 but not over the web without a Canadian credit card. Each additional 1GB is $30.
The setup process was pretty painful. It took about 30 minutes at the counter. Problems included web site errors, long SIM activation time, a seven page registration process, and a one minute delay to find the network after the phone is alive and searching. The rep said there were fewer problems with Android phones.
On the upside, coverage throughout downtown has been great so far.