I currently have a project under Unity Pro. How would I go about porting this project over to the Unity iPhone? Is it as simple as opening the unity iPhone and building it?
This project is also accessible through a browser via the unity web player. Would it be possible to access the project on a mobile device like the iPhone?
as simple as open and build: yes, potentially - depends on if you ensure to not use anything not present on the iphone like terrain or render textures (RTs are available with unity iphone 3 pro though but not iphone 1.x)
But it will not do much as you have no input due to its desktop focus. There might very well be quite some optimization related thing that you will also need to do to get more to see of it other than startup with a following crash or to be in the right size.
webplayers are desktop only, there is no mobile webplayer, apple does not allow extensions on the iphone