In reply to RX-78:
Pretty much all ski schools and guides offer off-piste skiing or even touring skiing courses or private lectures.
That being said, how good of a skier you are on piste? Because if you can survive the touron/tourist moguls in the afternoon rush down to the village in good style (so skiing and not some uncontrolled sliding on skis like the majority of people)... well, then you don't need any courses and could simple start hitting the off-piste (provided you don't get too far from the slopes, so no need to worry about avy-danger).
For that, I would reccommend smaller resorts (and ones that don't involve graciers). Namely for three reasons.
1. less competition for the easy pickings
2. less people on general, so more time skiing and less time in the lift que
3. cheaper tickets, living and so on.
And after spending at least 2 to 4 weeks of doing "safe" off-piste on your own. Go to an avy-course, so you can venture further form the lifts (and you can also assess the slopes you are going to ski).
Only after you are already confident in off-piste skiing and also assessing avy-conditions etc. would I try to book a ski-touring course (albeit that is not rocket science... so you could just get suitable gear and some mates & start touring).
Unfortunately I can't suggest any specific resort in the alps for lift served (and safe) off-piste. As the times I have been to the alps, I was already reasonably competent off-piste skier. But I would say, that some of the Nordic resorts migth actually be more suitable for training off-piste skiing.
As a last note, if you are even reasonable skier... the only course you need would be the avy-thing... and a proper course on it is atleast 2 full days, preferably more. So my advice would be to get competent at skiing on piste (which might require lectures) and then get on the deep-end and start practicing off-piste skiing on safe'ish locations on yer own (maybe get a private ski lecture from ski school for that, for like half a day or a full day... if you're skiing is not on-par with what you wish to do).