It's about 14 or 15 miles from John Wayne Airport (SNA) to Disneyland. If taking a cab, I'd say allow about 30 minutes for travel time; not sure about SuperShuttle time.
There are quite a few commercial carriers that fly out of SNA, including SWA, American Airlines (AA), United, Delta etc. I'd say this will come down to $$ for flights in/out and your preference for flight times.
We traditionally fly AA - because we can accumulate Qantas Frequent Flyer points with them - but we have flown United, Delta, Continental as well. For our May trip, I wanted to fly with SWA this time but the flight times didn't suit us.
You could either book directly on the carrier website; or try Expedia etc.