Your home wireless network: You already pay for Internet, right? If you primarily plan on using the iPad at home, then just jump on your home's Internet connection through your wireless router (providing you have one, which you probably do). The ipad will connect around your home network just like a laptop. Given the way Steve Jobs, Apple's co-founder and CEO, was lounging about on stage with it at its formal unveiling, it's obvious that's how they expect many people to be using them at first: casually browsing the Web, reading in bed (and buying stuff from iTunes).
Your workplace wireless network: Providing you're using it for work - and not for pretending to drive a race car in the bathroom - you should be able to ask your IT department to hook you up so that you can piggy-back off the company's wireless network.
3G: By paying a monthly fee to one of Canada's wireless providers, such as Rogers or Bell, you can get an Internet connection for your iPad anywhere you can get cellphone reception (provided you bought a 3G-equipped model, which are more expensive than Wi-Fi-only models). Rogers and Bell's price plans are identical: 250 megabytes of data per month for $15 and $35 for 5 gigabytes. This is a far cry from AT&T's 29.99 unlimited package - though not as bad as Germany's Euro 29.99 3-GB plan - but will likely be enough for most users. Bell hasn't said what it will offer, but it is unlikely to be vastly different.
Wi-Fi hot spots: If you opt for the cheaper Wi-Fi-only iPad, you can jump onto the Web via the hundreds of wireless hotspots spread throughout cities, from coffee shops and hotels to airports. Many of these will require that you either plunk down some money or buy a (possibly bad) coffee. Connectivity might be wonky on less established hot spots, though.
City Wi-Fi networks: If you live, work and/or play in downtown areas of some Canadian cities, or if you travel at all to the U.S. where public Wi-Fi hotspots are much more plentiful, you can hop online for a nominal fee. Also, many public libraries offer free Wi-Fi. In Toronto, for example, Cogeco Data Services is offering a cheapo $5 a month unlimited data plan on it's pre-existing fibre optic network in the city core. There are free or low-cost public Wi-Fi hotspots in places all across Canada, from Moncton to Vancouver. Visit this Wikipedia page for a few more links and locations.