also: http://gocanada.about.com/od/monthbymonthmontreal/p/July_in_Montrea.htm
The metro is slightly limited - in that there is no direct stop in Old Montreal, but only a few blocks away. You could easily spend a whole day strolling around the Old Port and Old Montreal. If you like amusement parks - LaRonde is a Six Flags Park.
Please check out: http://www.internationaldesfeuxloto-quebec.com/EN/programmation/calendrier.aspx Every year they have an international fireworks competition in Montreal - definitely a must see since your there during it. You can either buy a ticket that allows you to watch from under the Jaques Cartier Bridge at LaRonde - or even easier is to watch it from the Old Port - walk toward the tall clock tower (there is also a maze there). They start whenever it gets dark obviously - but it's usually around 9or 930pm. So go out to dinner in Old Montreal then take a walk to the pier.
For transport from Montreal Trudeau Airport to downtown: http://www.admtl.com/passager/acces_et_stationnement/home.aspx
It's only 2 hours drive between the 2 cities or you can travel by VIA Rail. Ottawa is walkable or you can get a taxi to the museums in Hull. Stay near Byward Market or the Parliament and your within a mile of most of the sites. There is an INFO office across the street from Parliament. There is also a pedestrian shopping street 1 block behind the info center. Check out the Rideau Canal, the gorgeous architecture and Byward Market area for lunch or dinner.
If you need more info on sights in either city, I'd be glad to help!


