The easiest way to book rail tickets is through the Oui.sncf website (Oui.sncf is the online travel agency of SNCF). There you are given the choice of an eticket (to print at home or to save on your mobile), or a hard copy ticket sent to you by mail. Either way, you can step straight onto the train without queuing up at the ticket counter.
Fédération Française de la Randonnée Pédestre (FFRP)
A full list of available Topoguides can be seen and bought from the FFRP boutique.
Institut Géographique National (IGN)
All the TOP 100 and TOP 25 maps, and the Topoguides, can be bought from the IGN boutique.
Géoportail is the French equivalent of Google Maps, but with far greater detail. This is very useful when designing your own route.
GR-Infos is a useful website for general information about GRs and GRPs.
My long walk
My long walk contains interesting diaries by an American who has walked extensively in Britain, but has also done two long walks in the south of France.