I use a Cingular 8125 Pocket PC as my cell phone. I run an Exchange server at home that I connect to for email, appointments, etc. The connections to that Exchange server run over SSL to keep communications secure. I use the cheap SSL certificates from GoDaddy.com. The problem with these certificates is that they aren't recognized by default on my Pocket PC. This meant that I was not able to sync my email with my phone -- the horror (my wife is rolling her eyes right now)! What I needed to do was install the GoDaddy Root Certificate on my phone.
I thought it was pretty simple, i could view the certificate in my browser and export the root of the certificate chain as a *.cer file and run it on my phone. The Pocket PC recognizes files of that type, but when I ran it the cert wouldn't import.
Fortunately I found a blog post about installing certs in a cabfile. By following those steps I was able to get the GoDaddy root cert installed andCheck out the Windows Mobile Blog for the step-by-step instructions.