RewriteEngine on

RewriteBase /
# if you installed facebook in a subdir use something like below and remove the line above
#
# RewriteBase /subdirectory/

RewriteRule ^admin/$ index.php/admin/login/
RewriteRule ^admin$ index.php/admin/login/

RewriteCond $1 !^(index\.php|application/images|application/scripts|application/css|application/content|application/settings|favicon.ico)
RewriteRule ^(.*)$ index.php/$1