In reply to Oujmik:
Hi there, it's worth going on the web and picking up a copy of Michel Piola's "Aiguilles Rouges 1" which covers the high crags from the Brevent to Cheserys, up near Argentiere. Make sure you're buying the English version. Loads of multi pitch routes on good rock and at the time you're going mostly approached in trainers. Loads of routes have been fully equipped by the guides, but there are plenty of things to do on a trad rack or combination of the two. Everything's very accessible from the various cable car stations along the valley. I suppose one of the routes on The Index is a must do, but very crowded. You'll also find solitude on a lot of the routes in the book too.
Also worth picking up Burnier and Potard's "crag climbs in Chamonix" which in addition to 1-3 pitch sports climbs, has a few longer easy routes from the valley floor like "voie Caline" which is 350m, equipped and there's a snack bar at the top! Recommended is l'ile aux Razmokets, 350m, 12 pitches at F6a max, and a brilliant restaurant/bar on the walk out.
It's also worth taking in the bouldering at the Col de Montets, and particularly Les Bossons, which is like a mini Font. All in the book.
Hope you have a good time.