The Citizenship and Immigration Canada (CIC) website has a great deal of useful information about applying for a temporary resident visa (TRV) (a visitor permit).
Explanation
For a full explanation of how to apply for a TRV, visit the CIC site at:
http://www.cic.gc.ca/manuals-guides/english/op/op11e.pdf [1]
In Depth Policy Manuals
For further in depth information you may also wish to refer to the following Policy Manual used by CIC:
http://www.cic.gc.ca/manuals-guides/english/op/op20e.pdf [2]
Application Forms and Guides
For the required application forms, visit the CIC site at: http://www.cic.gc.ca/english/applications/visa.html [3]
Useful Links
For links to various attractions and more see: http://www.cic.gc.ca/english/visit/links.html [4]