Please I need help it's very Urgent (Prevent un-authorized users to download document)

Hi All I built a MySQL table for all authorized users and their password , when user correctly enter his username and password he can access to a PHP site that contains a link to all document he need When he click on one of the document to he can download it, the URL will appear : http://www.myweb/data/data.pdf My problem is if any one get this URL or the path he can get the document without authorized. I need a way in which any one who try to get these document from the URL get a message to ask him to Login. __________________________________ Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com