don't go near the place at the weekends, thats the most valuable piece of advice you can get. Queues for rides can last up to 2 hours and from all accounts there is absolutely no pleasure in it at all. when there in Dec, I spoke with people who were at the weekend and they ended up leaving the place and heading into Paris itself.
Check out
www.disboards.com - go to the paris thread and there is a fantastic link which lists out all school holidays in France, Spain, Uk, Belgium and Germany. Avoid the French and Spanish holidya times, I was there in April for their holidays (booked before I found the link:-() and it was hell, queues for some rides went on 90 minutes, queues everywhere, for food, toilets, everything. WHereas went in early Decmeber and we walked onto rides, max queue was 15 minutes.
I booked flights through an Aer Lingus seat sale and booked an offer through disneyland.ie.
Used a private taxi to collect us from the airport direct to the hotel - it cost 60 euro for 2 adults, one child and it was well worth the extra cost as the bus is a nightmare and when I did try the TGV, there was a strike and didn't realise it until a fellow passenger explained what the French notices were saying!!
check
www.rollercoaster.ie - the the holidays forum there is a dedicated tips for disneyland paris thread