In reply to Somerville:
A Winter trip to the Ecrins?
If you are thinking of Winter alpinism and you don't have much experience or skill at ski-touring/familiarity with snowshoes or a lot of Summer alpine experience, my advice is don't.
It can get very cold indeed in the Ecrins in Winter, days are short depending on when you go and the avalanche risk is frequently considerable, while the weather can be ferocious. Most people, including Summer alpinists, steer well clear of the high mountains in Winter, those that do go are normally very good and experienced - or very naïve and foolish!
If roadside ice, there are several websites that give information of varying degrees of usefulness/timeliness :
http://www.ice-fall.com/ - particularly :
http://www.ice-fall.com/ri/Conditions/de/glace/307.aspx for individual areas.
Mostly oriented toward the East of the massif.
The guide book for most of the massif is now very old, Les six valleys in Oisans, though I think there is quite a new guidebook for the area around Briancon in the East. There are also quite a lot of coffee table type books appearing, normally you will need to get these (or at least order them from), France, typically in Grenoble or Briancon.
Rather than Winter, late Spring is a delightful time to be in the Ecrins, with longer days, often good weather. You will still mostly need to be able to ski or snowshoe though, depending on how high into the mountains you are going.