Ok, Someone posted a question about a counter in Flash before the switch happened, unfortunately that post is gone but here is the answer anyway:
Posted by Jubba
Its possible, but not with Flash alone. You need to use a server side script (like PHP) to store values into a text file or database. Then load the variables into Flash. here is a tutorial:
http://www.daydreamgraphics.com/tutorials/list/details/2/102