In reply to HosteDenis:
we did it at the end of August in 2007 and were in rock shoes from the start until the breche at the top of the tour rouge. Snow should not be a problem in summer unless there has been bad weather in the few days before, and then it will most likely only hang around in the shade on right side of the pillar, and on the crest at the top.
The route finding on the lower part of the pillar was pretty straightforward as I remember, just follow the path of least resistance. We passed the tour rouge on the left, which is how it is shown in the Piola topo. It was not immediately obvious to us where to head left and into the couloir, so we wasted some time trying to find alternatives before realizing where we were.
The topo you linked to on camptocamp is much more detailed than the Piola topo we used. There are several aid sections marked on the camptocamp topo that we didn't do - the only place I remember any aid is just below R15 (on camptocamp topo), where there is a steep, thin crack to get back left onto the crest of the pillar - a quick pull on a small wire was enough to get past this though.
You may well find pitching the couloir to the left of the tour rouge unnecessary - it was pretty much a scramble and we moved together as far as I remember.
One axe each, plus boots and crampons was fine in the conditions we had.
The way off the summit to the col du midi is straighforward and will be well tracked, but be careful as it can be very crevassed, and you'll be tired and could well be doing it in the dark.
Have fun, it's a great route.