Travelwest has a good journey-planning web page at
Traveline SW provides timetable information for all bus routes in the area.
Bus Checker is a very good app for smartphones and tablets.
You can find it here,
Next Buses gives departure times for the next buses due at your chosen stop.
This service is designed to operate from mobile telephones and similar devices and may not work on your browser now. If it does not, you can get an idea of the service at Next Buses for conventional browsers.
Please note: there are currently some gaps in the Next Buses information for some stops. We are reporting these to Traveline as we find them.