I’m sure a quick search will bring up loads of previous threads, in fact there’s one about riding in France somewhere on the front page I think.
However, my advice for first timers.
Drive v flying
Can be cheaper to drive if there’s a few of you in a van. 8-10 hours from the tunnel depending on luck and weight of drivers right foot.
We have in the past taken a van packed with bikes and everyone else fly out. Again depends how many are going.
If you are flying check out http://www.thecoolbus.co.uk and http://www.alpinecab.com for transfers. Used both before and they are recommended. Rob from Coolbus also does guiding in the Les Arcs area, top bloke.
Where to ride
Chamonix – very rocky and technical, less man made stuff, quieter trails
Morzine/Les Arcs – very popular, loads of DH and XC stuff, decent(ish) night life, loads of digs options from crap hole self catering to luxury hotels, trails take a right battering in late season especially if the weather is shitty, extensive lift system, massive full day routes an option
Les Arcs – good mix of riding, mostly hardcore XC biased though, quieter trails in better condition, a guide is highly recommended to find the best bits, most trails are off just one mountain/lift network so can be a bit samey. Less options for digs then Morzine although I would recommend http://www.chillchalet.com
Verbier Switzerland – similar in some respects to Les Arcs but maybe a bit more technical, small town consequently not much night life and cheap digs are hard to find other than ‘the bunker’ which is a dump. Again a guide is highly recommended, I’ve used http://www.powderanddust.com before and they were okay.
When to go:
Stick to mid season if possible, trails are less likely to be shagged and you’ve got a better chance of decent weather (although this is the mountains it can piss it down at any time). Plus the more people there means better apres ride atmosphere. ALthoug of course it will be dearer.
What bike:
Unless you are going specifically to ride DH an 150mm-160mm bike will be fine. Last time I went, I was on a Turner 5 Spot (the old type) and it was just the ticket for pretty much everthing including most of the DH courses, if a little bit slower ;o)