Cookie that redirects to 1 of 2 directories

[thegamebrain]

Have a bilingual site I'm putting together, /en folder and /fr folder.

Would like to have the default page (index.php) only contain this code. From this page, a redirect to either /en or /fr folder. Default folder would be set within the code, and the cookie would remember for 30 days that last folder the user visited - either /en or /fr

Anyone have a sample they can put me to?

Thanks!