we were just there in May 2010 -- had an 8:05. They let us in to the park at about 7:45, took 10 min. to walk up Main Street, time to snap a few pictures. We checked in just a minute or 2 before 8:00 and were seated by 8:05. We saw all the characters (party of 3 adults, no less) , had a great breakfast & we were out of there by 8:45 or so...took 40 min. start to finish to eat. Now the place wasn't even 1/2 full when we left, so that might have made it all quicker, but the characters were actually making a 2nd round when we left.
Even though you're in the park, they still have a "rope drop" inside the park -- you're not allowed to wander over into any of the other lands ahead of the rest of the park-goers. Even in Fantasyland, you can walk through the castle, but they have a rope across the walkway to Fantasyland and you have to stay there until the park is officially open...CM told me they actually drop the ropes inside the park a few minutes after the park officially opens so people don't have a huge advantage over those at the outside ropes.