I think this is the canonical source of links and information about the U.K and Europe canal system. Hours of reading.
One example I found interesting was the UK Inland Waterway Size Restrictions in English Units – make sure your boat will fit 🙂
Canal Boating in the U.K. and Europe
(with some North American information)
Being an introduction for those unfamiliar with the pleasures of canal and waterway cruising, as well as a resource for experienced boaters.
Nearly 2000 links to canal and waterways related web sites.