How exciting! First trips are great, be warned you may become addicted once you get a little of that magic. This will be unlike any vacation you have ever taken before.
I would recommend looking at Park Hours for your visit, sketching out a simple plan of what you are doing, like what days do you want to go to which park, then select ADR's for those Table Service credits on the dining plan and try to book them. Online booking is wonderful and gives you alot of flexibility. I also would recommend either spending alot of time here (or on wdw.com) reading the available info. The boards I would recommend for a first time are Resturaunts and Dining Board sub forum and Theme Park Attractions and Strategies. If you are a reader then pick up a copy of the 2010 Unofficial Guide to Disney, it is huge but has info on everything you need to know included strategies for planning days in the parks. You can of course skip the sections you have already gotten past (like picking tickets and a hotel) which will cut down the amount of reading.
Another thing I would recommend is keep an eye on the disneystore.com and watch for sales with a 6 yr old the opportunities for soveniers are endless and you can score some wonderful deals there. One thing I do is keep an eye out for cheap shirts and small stuffed animals and try to have something for everday. I'll either place it next to them in bed so they wake up with it or sneak back in the room after we leave and set something up. This will save you $$ from buying stuff in the parks.
