It's not difficult to find useful walking guides for the Brecon Beacons and Pembrokeshire, although if you want to tackle Snowdon, a proper guidebook is still a necessity.

Offa's Dyke - the Association and the Path
Offa's Dyke, for those unfamiliar with the Borders, was a low-maintenance, Dark Age version of Hadrian's Wall - a deep ditch and bank constructed by the then King of Mercia to mark the edge of his kingdom. The resulting 176-mile line is not in public ownership, but a path has been established by the Countryside Agency. The Association publishes an accommodation handbook which is now available online.

Wally Trimble's Walking Home Page
Wally is an academic at a US university who has walked both the Pembrokeshire Coast Path and Offa's Dyke. His observations, recommendations are entertaining, and his photography admirable.

Welsh Railways
Even before British Rail was privatised, Wales had a number of privately-run railways. Now the network is so complex that virtually every line is operated by a different company. This site explains where all the different stations are and when they are open, and links to the various official sites. Given the paucity of public transport in Wales, it's invaluable if you don't want to bring a car.

Walking Wales
A somewhat feeble effort from the Welsh Tourist Board, this site is really only of interest if you want to find a tour operator to organise your walks for you.

Brecon Beacons Guide
Undoubtedly the best site for walkers in the Brecon Beacons National Park, it has safety advice, lists of accommodation and featured walks. If your computer is fast enough, the site has a ten-minute video about the area; one page even reproduces poetry inspired by the Beacons. An extraordinarily comprehensive site which, while not as flashy as some of its rivals, proves a great deal more useful.

Pembrokeshire Coast National Park
Although far from easy to navigate, this site conceals a step-by-step guide to the National Trail, a guide to public transport and local accommodation and details of some of the attractions on the way - Carew Castle, the many beaches and Pembrokeshire's five main islands.

North Wales Tourism
Currently in beta production (which means that it is still being built), North Wales Tourism's site concentrates on Anglesey, Snowdonia, the coastal resorts (such as Barmouth) and the border. It is of general interest and not yet especially useful for walkers.