Montreal Accommodations

If you are sure of the days you are going to stay in Montréal and are OK with non-refundable advance payments and are booking a week or more in advance (so as to get in multiple offers over multiple days), try Priceline -- amazing deals are possible -- pay 40-60% of the prices normally charged at the hotel web sites, in some cases. Good discussion boards for Priceline include (search for Montréal) and BetterBidding (search for Canada). If Priceline does not work out, Hotwire hotels section is also worth a check. Note that both Hotwire and Priceline do not display hotel name until after you pay for it, and only a single double-bed is guaranteed though you can request options and sometimes the hotel will honor them.

For those visiting for a week or more, a great option is to rent a room or an apartment. This is a great way to live like the locals and explore neighborhoods. This is fraught with some risk in that the people renting may not be totally dependable - you may find that the person is not around at the agreed upon time, or that the place may not be as promised. But the advantages are many, and this also is usually less expensive than a hotel. There are large number of choices that can be browsed online - the one good site is short term rentals and if you really feel adventurous and can put up with miscategorized postings and can spot scams, another site is craigslist sublets. (But in some cities, this applies: Craigslist full of rental scams.)

The number of choices is large if you are traveling without a car, but if car parking is necessary, look for places outside the downtown area where street parking is easier. Alternatively, you can leave your car in a parking lot but that can cost $25 or more during peak holiday times in the downtown areas.

Some other links:
Hostelling International, Montreal Dorm-like bunks, as well as some private rooms. Very good location. Studio apartments near Beaubien Metro. Outside core Montreal, but room is nice, and landlord makes renting very efficient and easy.
Kijiji Short Term Rentals Site is sometimes hard to use - but has a good variety of rentals. Risk here is that the person renting it out may not be reliable. I've personally had trouble only once when the person renting cancelled my rental without telling me. So, use your judgement and verify booking again a few days before you arrive.