Preloading large .swfs

Hello all,

I have a main.swf file which has a variable that loads 6 quite large photo based transitions (approx 50kb) in and out of the movie.

They work fine and they look good on say a 4 meg line, but on a slower connection and if the internet is being a little slow they lag a bit. Once they are cached they run smoothly:

http://www.start-london.com/

As you can see from the link there is an intro page.

Is there a way that a I can preload the transitions while this intro page is showing? Or even on the first transition that loads into the main stage?

Or how do I display a loading graphic/movieClip between these transitions?

Ideally I guess I would have both a preloading function and a loading bar…

Thanks for any help in advance.

Henry