There are reasonable books for sale describing the route - check in any climbing shop or even the big Payot bookshops

Not sure how many hours you want to walk but the best sections of the route that you should try to include are

Col de Bonhomme; col de la Seigne; col de Ferret; fenêtre d'Arpette; col de balme 

If you are not doing the whole walk then avoid the section betweenFerret and Champex and the Chamomnix valley which you can do any time from Geneva on a day trip.

Do not forget that you can get a bus every hour from Courmeyeur to Chamonix which is less than 10 euros and gives an incredible flexibility in your planning

To be sepcific I would do

Day 1 Contamines, refuge de col de Bonhomme,

Day 2 to Refuge de

Day 2 to refuge des Mottets

Day 3 to refuge Elisavetta

Day 4 to Courmeyeur

If you are good walker you can do this in a weekend but 8-10 hours per day

This would give you the option of starting from Les Houches o lengthen the walk.

Alternative Start from Courmeyeur and stay in the refuge below the col de Ferret; next day to la Fouly; then bus to Champex (or you can walk) and over the fenetre d?Arpette fir the col de Forclaz

Following day over col de Balme to La Tour or Argentiere

to get an Idea of the routes that are possible go to www.chamonix.com and click on the ultra trail  

and try this http://www.circuitsderando.com/tmb/index.htm

Just looked at the website (the second one) and it looks to be very informative. There might be better ones but I just googled tour de Mont Blanc

Once you chosen a route and you have specific questions on preferability of one route over another, send me a msg on glocals

Also bear in mind many huts start closing around mid to end september so you need to chose your route quickly and then fine tune around the huts which are open. Normally all poart s of the tour can be done provided there has not been excessive snow falls 

It's a bit cooler now to do the TMB, anyway i also did it 10 yrs ago for 4 days and below are bits and pieces of what can find in my notes.

4 days - Champex in Switzerland to Montroc in France.

. I recalled starting at Champex and took the the trail going to Fenêtre d'Arpette (spectacular views of the huge Glacier du Trient).

Refuge: Col de la Forclaz

Day2. Trail le Peuty and up to the French - Swiss border at Col de Balme, Then take the trai going to Col des Posettes with an ascende to the Aiguillette des Posettes.

Refuge: ???

Day3. Take the trail to Col des Montets and then ascend to a platform above the valley direction Lacs des Chéserys (i had a superb swim in the surprisingly warm water with the view of the mt. blanc).  We continued up to lac Blanc, where we had a drink and a look around.  We descended to
our refuge at la Flégère. Enjoy the view of the mt. blanc at night !!!

Refuge: la Flégère

Day4: Take the lift up to continued up to the Col de la Glière and hike down direction col du lac Cornu. Continue down to the mid station at Planpraz.  and ascend to col du Brévent. Descend through grass-covered meadows with views of Lac du Brévent to the Refuge de Bel Lachat. Walk upt to Les Houches picking some rspaberries on the way to the TMB train station.

thank for the the response.

you know a place in geneva that i can buy a map and a guide book for the treck? (and wich of the kinds)

Cactus Carouge or any sports shop

The big book shop on rue du Mont Blanc either Payot ir Naville, Buy the blue French maps 1:25000. Which map you buy depends on which section you are doing. The amps are cheaper in france.$

If you buy a guide book you probably do not need a map

And the website I mentioned above describes the roiute (if you only use that a map is usefu¨

Best guide for non Franch speakers is published in English by Cicerone. They ought to have it in Geneva