Check into Long Beach airport as well. It's often as cheap or cheaper than LAX.
I was writing some tips out and did a little summary of airports and airport transportation; I'll paste it here:
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Airfare and airports
Start checking your airfare as far in advance as possible. There are four possible airports to fly into, and they all have pros and cons.
LAX, approx. 35 miles away: pros, often the cheapest and has the most flights and times available, Disney Resort Express bus runs on a frequent and convenient schedule. Cons, can be expensive for ground transportation because its the farthest away; its your typical huge, dirty, loud international airport.
ONT, Ontario: approx. 30 miles away: pros, often fairly cheap to fly into, not as big. Cons, ground transportation can be pretty expensive since its quite a distance
SNA (also known as Orange County or John Wayne airport) approx 12 miles away: pros, the closest airport, small, yet very nice and convenient.
Disneyland Express also runs here. Cons: its usually the MOST expensive of all the airports. Dont know why, but it costs us over $100 or more extra, per person, to fly into SNA. However, shuttles are cheaper from here.
LGB, Long Beach, approx 14 miles way: the choice of many. It is a small, clean, quaint airport (you deplane down stairs onto the tarmac!) and nearly as close as SNA; yet it can cost considerably less to fly into. Cons: ground transportation can cost more here; Super shuttle is 3x as much for some reason, although a taxi will cost you the same as from SNA ($40 flat fee one way). Disneyland Express doesnt operate from here.
Ground Transportation
As mentioned in the airport amenities, you have several choices. You can rent a car. I think theres no real reason to, if you are staying at a hotel within walking distance and not going off on side trips to the beach or San Diego, etc. See Hydroguy's Hidden Time Losses when Using a Car at DLR
You can take the Disneyland Resort Express Bus. Grayline Disneyland Express Its a big charter, and it stops at the DL hotels first. Its very convenient. From LAX, its $30 RT for adults, $22 for children 3-11. From SNA, its $25 RT, $17 for kids.
You can take a taxi. From SNA and LGB, I have read that there is an established flat-rate of $40 one way. (but I dont think you can get the same flat fee returning to the airport; Ive heard its more like $55.) If you have more than 3 people, its probably worth it. There are supposed to be taxi vans that can take more than 4 people, but I have not heard that theyre always available, and we didnt see them while we were there.
You can use a shuttle service. Super Shuttle and Prime Time shuttle are often used by people on the boards. Ive heard some stories about slow or poor service from Super Shuttle, but its the cheapest way to go for us ($36 RT for both of us!) so thats what Im doing. These companies also offer private vans for larger groups, or private car services. You can get coupons for a dollar amount off in the Entertainment book (I used one for $2 off per person with ours).
You could spring for a limo (ok, that doesnt go with my budget theme). But its been done and it could be a lot of fun. If you have a group of 5, 6 or more, and you were thinking of getting a private shuttle van for around $100, you could probably get a limo for around $150, one way, maybe less. Id get a recommendation from the hotel. We did the limo for a surprise, and it was very fun, but I should have researched companies better; I wasnt impressed with the service we had. (I dont recommend Starz Limo!)