The first thing you need to do is pick a resort. When you are going to Disney the best thing to do is stay on property. Disney has a resort to fit ANY budget, and they have two things the off site hotels can't offer, the famous Disney service and PERKS. Disney takes great care of their resort guests. For example, they offer free shuttle service with luggage drop off to and from Orlando Int'l Airport. They offer Extra Magic Hours, where one park is open late and one early each day for resort guests only. They also offer free unlimited use of their transportation system. Now that does not seem like a lot, use of the transportation system, but when you take into account that the off site places only have limited shuttle service an in many cases it costs extra, or you have to DRIVE every day to WDW it is a huge extra.
There are 4 different levels of Disney resort. The value resorts are just that, value. Now don't get me wrong they are great places to stay. The themes and decor are bright and bold, the pool at each place is huge, there is a food court and bus services. However the rooms are on the small side, there is ONLY the food court. These resorts tend to fill up quickly as they are geared toward families, so if you want to stay in a value resort I would try to make reservations right away. My favorite in this category is the All-Star Movies resort.
The moderates are one step up from the values. The rooms are bigger, they have multiple pools, there is a food court and a sit down table service restaurant. The themes and decor are again out of this world. These resorts are much larger, and have dedicated bus lines to and from all of the Disney attractions (the All-Stars in the value category in most cases share a bus line.) These resorts also have a few more things to do on the resort itself, such as bike rental, boat rental, and a few other activities. My fav in this category is the Caribbean Beach resort.
The deluxe resorts are the cream of the crop. They are all located around the Seven Seas lagoon in front of the Magic Kingdom and are connected by the monorail system (except for the Animal Kingdom Lodge.) They offer the most amenities of all the resorts, with multiple dining options including character meals, the rooms are all fairly large, multiple pools and many other activities on the resort itself. These are also the most expensive. My favorite of these and fav overall is the Polynesian. When you enter the Polynesian it feels like you have entered a tropical paradise, not a Disney resort.
The vacation club resorts are a little tougher to get into than the others, mostly because many of the rooms are reserved for vacation club members first. These are the home away from home resorts, with multiple levels of room size and anything from a kitchenette in the studio rooms to a full kitchen in the two bedroom and Grand Villa rooms. These offer some of the best recreation activities if you like golf and tennis, and in a few cases they are within walking distance of a few of the parks (the Boardwalk is right next to Epcot, Saratoga Springs is right next to Downtown Disney.) My favorite in this category and a close second to the Polynesian is the Saratoga Springs resort.
When purchasing tickets add the park hopper option. The park hopper gives you the ultimate in flexibility when visiting Disney. The base ticket gives you entrance to one park each day, while the park hopper allow you to come and go as you please. For example, let's say you spent much of the day at the Animal Kingdom. That park closes earlier than the others, so after a midday break at the resort you decide to try to catch the Fantasmic night time show at MGM and ride the Aerosmith Rock 'N' Roller coaster. You can ONLY do this if you have the park hopper option on your passes. Or for example you enter the Magic Kingdom, but after a little bit decide it is too crowded. If you have the park hopper you can jump on the monorail and head over to Epcot, which is usually not as crowded. Without the park hopper you are stuck. It just gives you more flexibility with your trip, and less headaches.
There are a few websites that are very helpful when planning a Disney trip. First, check out the Disney website. They have full color pics of each resort with descriptions, and a resort comparison tool so you can pick the resort that is right for you. Next, check out the DISboards. The disboards is a message board website all about going to WDW. It is free to register. Here you can get resort reviews, restaurant reviews, tips for avoiding crowds, trip reports, tips and advice, ask questions and much more. There is more info here than you can possibly need. Allears.net is another good one. Finally, go to the bookstore and pick up the Birnbaum's guide to WDW. There are a ton of guide books out there, but that is the one that has worked best for us.
Hope this all helps, have a great trip!!