Folders under a root web site can be converted to subwebs with their own permissions for who can author, browse, or administer them.
To convert a folder to a subweb, do the following:
While connected live to your website, go to the folder list, right-click the folder you want to convert to a subweb. Click Convert to Web on the shortcut menu.
The larger the contents of the folder, the longer it will take to convert the folder to a web site. For a large folder, this process could take several minutes.