EDIT: Just read this:
Note: Live coverage of the shuttle launch continues during the first period break of the NHL game between the Chicago Blackhawks & Minnesota Wild. If the shuttle launch happens during the second period of the hockey game, hockey viewers will see the launch during the break after the second period.
For Canada --- HDNet brings viewers in Canada uninterrupted NASA coverage from 7 PM - 9 PM ET.
They are also discussing wind issues at the launch. 47: after the hour for launch if it holds.