Hi and welcome.
You can make dining reservations 180 days before your first day at WDW, generally. However, they are implementing some sort of new dining computer system, so right now you cant make any reservations (dining) for 2009. That should change sometime this month. (Plus, you can make reservations at Cinderella's Royal Table & Chef Mickeys, even for 2009).
Sounds complicated, huh?
I would say, pick your dates, pick your resort, then read some of the books like the Unofficial Guide to WDW & these boards. Once you know which rides & attractions you most want to see, you can plan where to spend each day. Then, once you know where you'll be, you can make those dining reservations.
For family fun, we like Cinderellas (but $$$$), 'Ohana's at the Polynesian, the Sci-Fi cafe at DHS, the Rainforest Cafe (at AK or DTD).
We love all 4 parks & the 2 water parks as well. With 2 weeks, you should have time to visit all of them.
We actually leave the MK until the end. It's classic Disney and sure to please the kids. We do Epcot, DHS, & AK first. Kids like Epcot more if they are not just coming out of the MK!

. And the kids passports at Epcot are great for keeping them happy when touring the countries.
For us, it's better if we walk in with a plan of what to do each day. Then we dont spend tons of time thinking: what should we go on next? We also get to the parks at opening, take a swim & a rest at our hotel during midday, then go back to the parks in the evenings. Some people can tour from morning to midnight, but we get tired and cranky.
Have a wonderful time planning your trip -- dont worry -- the planning part can be fun!
