If you are bringing a tri-band mobile/cell phone with you which is set up for roaming you should have no trouble using this in Vancouver.
NOTE: It is illegal to drive in British Columbia while using a cell phone. If you are caught talking, texting or looking at the screen of a mobile device you will be fined $167 CAD.
The international Country Code for Canada: +1
Vancouver Area Code: Either 604 or 778
The area code for the of British Columbia: Either 604 or 250
If the number you are calling is outside of the Greater Vancouver area you have to add a 1, such as 1-604 or 1-250.
You can find the phone numbers of most residents and businesses (as well as see a map of their location) in Greater Vancouver and BC by using the following sites:
Other Useful Phone Numbers
Vancouver Tourist Information Centre: 604.683.2000
TransLink Information (Public Transit): 604.953.3333
Weather Report: 604.664.9010
SuperNatural British Columbia Information and Reservations: 1.800.HELLO.BC (1.800.435.5622) in North America or 250.387.1642 from overseas