The route is described in detail with good maps in: Last modified September 2010
Tour du Mont Blanc: Books
GR-TMB - réf. 028 - Tour du Mont Blanc - Plus de 10 jours de randonée
This guide is written in French, but that may not be a problem. The route is waymarked rather well and the maps in the guides give enough information if it is not clear where the route is going. In the booklet estimations of walking times are given, which were good when climbing and most of the time too short when decending - especially for me.
15 Years ago we did the GR5. One of the english booklets we used then also contained a full description of the TMB with detailed maps. In Italy the route was changed over the course of years, in Switzerland and France the route is still as described in our booklet.