As it turns out, it’s pretty easy to install new root certificates on the iPhone. All you have to do is grab the certificate file in PEM format (via e-mail or web, either will work) and then open it up. Simple as that. In my case, since I wanted to grab the CACert root certificate so that I could use the WordPress iPhone application with this blog, all I had to do was navigate to their Class 1 PKI Key in Safari on my iPhone and I was presented with an installation dialogue. After clicking ‘Install’ I was ready to go.
Perfect! Thank you! Just what I was looking for!
-JT