I recently spotted a tutorial here: http://www.msfn.org/board/index.php?showtopic=19527

A great tutorial on the subject of subdomains.

I tried using the suggestion with an htaccess file that reads:

RewriteEngine On

RewriteCond %{HTTP_HOST} ^cfhealth.cfcure.com$ [OR]
RewriteCond %{HTTP_HOST} ^www.cfhealth.cfcure.com/MT/$
RewriteRule ^(.*)$ http://www.cfcure.com/MT/cfhealth/ [L,R=301]

basically I want cfhealth.cfcure.com to be redirected to http://www.cfcure.com/MT/cfhealth/

I uploaded the .htaccess file to my www directory, and I tried the subdomain, but it failed to open, saying :: Safari can’t open the page “http://cfhealth.cfcure.com/” because it can’t find the server “cfhealth.cfcure.com”.

What did I do wrong?

Sounds like you don't have a DNS entry for that subdomain. The redirect won't work if DNS never gets you there to begin with.

what about Vhost .. have you tryed that ..

i dont know anything on the RewriteEngine rules .. to help there .. but i just use Vhost for my subdomains when i do testing