Shaw system:
Here is what I have been told by Shaw, (and a tech in CA):
Available if you have a BC, Alberta or some eastern provinces address for service.
The footprint of the original Shaw satellites, Anik I, Anik II covers all of the lower 48 US, bits of Mexico, most centers of population in Canada,.
The Anik I and II will not be there forever, as the FCC rules have changed since they were launched and Shaw has launched a newer, FCC compliant satellite that doesn't work in the lower 48 or Mexico. Any new installation will be given access to the newer satellite, not the older ones. If you have issues with your service and call Shaw for help, they are not allowed to help you if they know you are out of the allowed service area (FCC rules).
As i now own a site, so don't point my dish at their satellites from a multiplicity of different locations, I have tried the local cable Co this year, Time Warner, and for $10 per month on top of my internet account, I get more TV than enough. Shaw went up this year to $40 for a basic package.