Getting Around: 
Montreal has an excellent métro (subway) and bus system. Buy the strip of 6 tickets which is the best choice for most tourists taking around 3 trips per day, but don't need to use it for multiple days. For three consecutive days, the 3-day tourist pass is good deal. For tourists visiting for a week and starting on Monday, buy the CAM hebdo - a weekly commuter pass. Subway to bus transfer or vice-versa is free to continue a journey, remember to take the transfer ticket from the automatic machines just after entering the turnstile in the metro, or get it from the bus driver on a bus. More details on the Metro at the STM Metro and Bus official web site.
Parking is a major hassle on the streets downtown, and parking lots are very expensive. Moreover, driving downtown is just no fun, especially along Ste-Catherine (always avoid), or the lower part of St-Laurent. Avoid driving as much as possible. For any street parking, be sure to learn enough French - names of the days of a week at least - to navigate the multiple signs that apply to street parking.
East-West street addresses in Montreal will have an East (Est) or West (Ouest) designation. The street that separates East from West is boulevard St-Laurent, also known as the Main. This is very important because looking for 4400 Jean-Talon without knowing if that means East or West of St-Laurent would mean a lot of time spent in searching to find the right place!