Wordpress Category Rewrite

Hi all. Htaccess n00b here, but I'm learning.

I'm trying to make this Wordpress link: http://sub.example.com/category/dallas/
Look like this: http://sub.example.com/dallas/

I can do a 301 redirect just fine (see commented out section below), but I can't rewrite the URL. :-/

Anyone have any idea what I'm doing wrong? - Thanks!

# RewriteEngine On
# RewriteBase /
# RewriteRule ^dallas/$ /category/dallas/ [R=301,L]

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^dallas/$ /index.php?cat=5 [L]

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress