Passing var from link to preldr to swf

I have a link to a page that needs to pass a variable to the preloader swf within that page.

The preloader than uses:
loader.contentPath = “testing.swf”;
… to load the second swf.

I also need to pass that same variable to the second swf to have it load a specific scene.

I am new with flash and need all the help I can get.

thx