Thanks for the suggestions. We have a separate mobile site and I still give people the choice, but this is mainly for Twitter feeds. It's working. I got help from here:

http://corz.org/serv/tricks/htaccess2.php
[download]

If anyone else needs this I got it to work by doing this in the .htaccess:

RewriteCond %{QUERY_STRING} ID=(.+) 
RewriteRule ^articles/(.*) http://www.site.com/cgi-bin/mobile.pl?$1 [Q
+SA]
[download]

It only forwards people who use mobile browsers and who click on a link that specifies an ID in the query string. Everyone else is routed normally. Thanks. Thanks for the help.