Exchange 2007 has a new feature where it can be installed from a command line. This also allows for easily scripted mass installs for the enterprise, or a way to better standardize builds across many engineers or locations. You can test it out at the TechNet virtual labs mentioned in my previous post.
"To ease deployments in large environments, Exchange Management Shell scripts can be used to automate server installation and provisioning."
>exsetup /roles:clientaccess /mode:install