quick .htacess password question

[eluser]umbungo[/eluser]
How do i block access to a specific subdirectory of a site??

eg. i have admin.php in http/application/controllers/, which is loaded from example.com/admin; how would i go about password protecting just this part with .htaccess?

(FWIW: I have the password file set up, and i have sucessfully been able to block the entire site.. just not specific directories)

[eluser]nikes[/eluser]
Direct storage

[eluser]umbungo[/eluser]
??

[eluser]umbungo[/eluser]
Anyone?? (i don't know what nikes was alluding to)

[eluser]umbungo[/eluser]
So??? Is this impossible and requires PHP auth then??