Amy,
I know it can be overwhelming, but we are more than happy to help! I think the Passporter books are a great place to start your trip planning, as they provide a nice overview of the resorts, parks, restaurants, etc in a very user-friendly format. They are also an independent company so you get 'real' opinions and not official promotions. I used them to plan our first Disney vacation and I found their reviews to be very accurate.
Once you have a better feel for Disney, I recommend checking out
www.allearsnet.com. This site is amazingly detailed and I especially like the restaurant menus for help in deciding where to eat.
Next I head back to the main Disney site, where I look at the calender page to determine the hours of operation, parade and show times, and other important notes on refurbishments, closures, etc. I make myself a printout of the park schedules and decide from there which park we'll be at on which day, then make my meal reservations accordingly.
As for the length of stay, that really depends on your children. My girls are about the same age and have never had a problem with the 11 day vacations we typically take. I have a friend whose daughter was ready to go home on day 3! My general touring advice is to take a 6-day trip and allow 2 days each for Magic Kingdom and Epcot, and 1 day each for Hollywood Studios and Animal Kingdom. Because your boys are younger, if you want to save time I think you could easily cut back on time spent at Epcot and Hollywood Studios in order to shorten your trip. The majority of rides and attractions for them will be at the Magic Kingdom, so I'd concentrate most of my time on that park and pick and choose what you want to experience at the other 3.
Your boys are at a very fun age for Disney, and I know you'll have a great vacation!