Rogers runs their own network in Saskatchewan (which sucks, 3G coverage only in Regina/Stoon, EDGE everywhere else).
Bell/Telus (pretty much same company as far as mobility is concerned?) were smart enough to just partner with Sasktel rather than putting up their own towers.
Sasktel is a terrible company, but I'm happy with my Bell phone service. Its much better than Rogers (horrible coverage (in SK), horrible speeds (in SK), horrible plans).