For instance I want to set up a CNAME for a mail subdomain to easily access our Google Applications Mail.

IE: mail.simplifive.com -> mail.google.com/a/simplifive.com

I cannot get this to work .... any ideas?
 

I've never used Google Apps, but is this what you're trying to do, or have you done this first?

http://www.google.com/support/a/bin/answer.py?answer=47283

It looks like your CNAME should point to ghs.google.com???