Hi Moes87! You are going to have so much fun! There is nothing like that first trip to WDW!!
As mentioned previously, pick up a copy of the Unofficial Guide to WDW. It has tons of info - everything you need to know. It also has touring plans which will help you navigate your way through each park. The plans work great and help to eliminate some of the "wait" time. It details all the rides and rates them based on age groups, and what to expect, so you won't end up on a ride that your kids will be terrified of.
Depending on how long you're staying, I'd recommend visiting Epcot first, AK/MGM next, and MK last. MK tends to be the favorite for many, and Epcot may not hold up to the younger kids expectations after visiting the best first! Try to plan on some down time, if you're staying on-site, so that you don't get overwhelmed by it all. By all means make plans, but try not to go into "commando" style, where everyone has to stick to the pre-determined plan. Allow for people's mood to change, and expect the kids to get tired and cranky at the end of the day!
Having said all that, here are just a few suggestions apart from the usual rides:
1) ride up front on the monorail. Simply ask an attendant if you can, and they'll do whatever they can to accommodate you. If someone else is already waiting to do the same thing, if you have time, simply wait for the next train.
2) buy some Micky ice cream bars - delicious!!
3) get the kids to search for hidden Mickeys throughout the parks
4) pressed penny machines - great (cheap) keepsakes!
5) take in the parades and fireworks. The maps at each park will give you the times if you don't have enough time to research them before you leave. Some parades are in the afternoon. Fireworks, of course, are in the evenings. All the parks have a parade at some point during the afternoon or evening.
6) plan on a late afternoon/evening at MGM so that you can take in Fantasmic.
7) take a bee-bee gun on It's a Small World After All ride to take out some of those dolls! Just kidding - but it's such an annoying ride, (IMHO), you have to ride it at least once!
the list could go on and on....! Don't worry about trying to see it all on this trip. You can't! It's impossible! So go through the book, decide on what you feel are "must do's" for you and your family on this trip, and save the rest for your return trip next year!