There is an official
Disneyland Resort Bus from John Wayne/Orange County Airport and LAX - the 2 routes are served by different buses. It's really inexpensive and operated by Grayline Buses.
The cost is $14 one way/$24 roundtrip for an adult; $12 one way/$16 roundtrip for a child, plus tip.
Here's the link to a $3 off coupon - I found it on MouseSavers website.
http://graylineanaheim.com/images_new/coupon_GrayLine_Shuttle_2007.gif
I haven't taken them myself in years (since I moved here to the LA area), but I used to be a weekly business traveller out of the LA airports and would do a non-stop option like that over Super Shuttle. With Super Shuttle, you get loaded up with other families and have to make several stops to drop them off. Plus, some of the drivers can make you a bit queasy....
Have a great trip!
Nancy