Number ports often take a little while (a day or two) to fully complete, basically a business day or so for all the network-side machinery to get updated about the change. So it's one of those problems which usually sorts itself out - don't panic, be patient, and restart your device every few hours until it starts working.
You will need to configure APN settings (and restart) to get data and msg attachments working properly, but you can't really do that until the phone properly connects to the network.
The phone may report "Telus" instead of "Public Mobile 3G" for a little while but this doesn't seem to cause any issues and, again, it tends to sort itself out after a while.
If you just can't get it working then try your PM SIM card in another unlocked phone. Or ask a vendor (like London Drugs) to configure it for you while buying a PM payment voucher.