Busabout.com: Busabout is an innovative hop-on hop-off travel service covering 41 countries in Europe. Tickets and passes are flexible and you can make your own route and itinery according to your own timeframe. Online ticket booking available.
National Express: Check coach schedules and timetables and book coach tickets online for the uk and europe.
Showbus.co.uk: Excellent portal site linking to bus timetables online all over England and the uk, also links to regional transport authorities / companies sites.
Translink Journey Planner for Northern Ireland: Check bus and train times throughout Northern Ireland up to 28 days in advance.
Transport for London: London bus timetables, routes and journey information, also include fares, transport zones and season ticket information.