The best recommendation I have for you is to look at the enterprise deployment guide. I put in a link for you below. This will walk you through the steps needed to get your environment ready for and iPhone. Also check out the configuration utility, make it easy to deploy settings ssl certs etc.
Enterprise Deployment Guide (iPhone)
http://manuals.info.apple.com/en_US/Enterprise_Deployment_Guide.pdfiPhone Configuration Utility
http://www.apple.com/support/iphone/enterprise/