check for registration on a directory

[Jakeman]

what i want: check for registration (login cookie) when entering the "files" directory on my server. nothing special at all... simply an "if registered then load directory else show default no access page".

i assume this involves a .htaccess file...

i already do this with my jpilot chat integration in the php script i made for it. but .htaccess isn't php so i'm not sure what to do here.