Regulation
The CRTC (Canadian Radio-television and Telecommunications Commission) is the government body that regulates the communications industry in Canada. The CTRC grants licences to operate television channels, and controls what type of programming is shown. A station in Canada (generally) must show a certain percentage of Canadian content (CanCon), and must show the type of programming specified in its license.
Delivery
Cable television has been ubiquitous in Canada for many years, and satellite television is becoming increasingly popular. The cable market is controlled mainly by a few large players (Rogers, Shaw, Cogeco), and has recently been going digital to compete with direct to home satellite. On the satellite side, Canada has two providers (Bell ExpressVu and Star Choice), which is quite amazing considering how small the market is (in comparison the US, if an inductry merger is allowed, will have only a single provider).
Channels
The choice Canadians have as far as programming goes has become staggering in recent years. Due in large part to the widespread ownership of digital cable and satellite systems, Canadians can enjoy many hundreds of television channels (in addition to pay-per-view and audio offerings). Furthermore, except for the main American networks and some international news services, all channels are Canadian based and must show Canadian content. Besides the usual network (CBC, CTV, Global, etc) and local channels, the speciality offerings are bewildering:
Aboriginal People's TV Network
ACCESS
Animal Planet
Arts & Entertainment
BBC CANADA
BBC World News
Beats per Minute
Black Entertainment Television
Book Televison
Bravo!
Cable National Broadcasting Center
Cable News Network
Cable Public Affairs
Cable Pulse
Canadian Learning Television
Canadian Odds Channel
CBC Newsworld
Country Canada
Country Music Television
Court TV Canada
Crossroads TV System
CTV Sportsnet
CTV Travel
DejaView
Deutsche Welle
Discovery Civilization
Discovery Health Canada
Discovery Kids
Documentary Channel
Drive-In Classics
Edge TV
English Premiere Soccer
ESPN Classic Canada
Fairchild
Fairchild - Movies
Fashion Television Channel
Fox Sports World Canada
GameShow Network
Headline National News
i channel
Independent Film Channel
Jockey Club
Live Horse Racing Channel
Lonestar
Men TV
Movie Central
Movie Central - Adrenaline Drive
Movie Central - Comic Strip
Movie Central - Encore Avenue
Movie Central - Heartland Road
Movie Central - Shadow Lane
Movieola
MoviePix
MoviePixToo
MTV Canada
Much More Music
Much Music
MuchLoud
MuchVibe
Mystery
Newsnet
NHL Centre Ice
NHL Network
One: Body, Mind & Spirit Channel
Outdoor Life Network
PBS
Playboy
PrideVision
Prime
Raptors Channel
Report On Business Television
Scream TV
SexTV
Showcase Action
Showcase Diva
South Asian Network
Speedvision
Star Network
Talk TV
Tech TV
Telelatino Network
Teletoon
The Biography Channel
The Comedy Network
The Discovery Channel
The Family Channel
The Food Network Canada
The Golf Channel
The History Channel
The Home & Garden Network
The Knowledge Network
The Learning Channel
The Life Network
The Miracle Network
The National Geographic Channel
The National Network
The Saskatchewan Network
The Score Television Network
The Shopping Channel
The Sports Network
The Weather Network
Treehouse
TV Land Canada
TVOntario
Vision
Weather Channel
Women's Sports Network
Women's Television Network
WWF Power Slam
XPRS Channel
Xtreme Sports
Youth Television
(Note: this is not necessarily a complete list, it's just what I hacked together from several sources).
...and that's only the English channels (there's a smaller, but still very large, selection of French language speciality channels) - all this for a country with only about 20 million English speakers! New channels are added periodically (40 odd channels were added in the last year), but they'd be hard pressed to find something not covered.
To see what's new in Canadian television, check out http://www.newtvchannels.com, a website run by the industry to tell people about what's new (and, more to the point, how they can start paying for it).
Much better than Australian television, where you can count the number of channels on your fingertips :) | 
