Passign vars between swf's

i’m wondering how best to do this:

i have to separate swf’s, and i need to pass a var from one to the other

initially i thought i could write the var to a text file (do this from the first swf) and then load the var in the second swf

is there an easier way? (i.e. i’m using getURL in the first swf to launch the second swf. could i pass it in that?)