Custom Greeting on Pages When Not Logged In

[donw9876]

Hi -

I would like to add a feature to my SMF community (currently running 2.0.10) such that - the main page of the entire community would display a message of my choice when the visitor is not logged in, and perhaps a different message when they are.

It would also be nice if individual forum index pages could have their own custom not logged in message also.

How would I do this? I don't know where to start. I do know PHP, HTML and CSS so I'm educable. Is there a mod that does something like this? Or is there a way to inject my custom PHP into every page? Or would this be a code variation of an existing theme?

The idea is that I want a call to action message for visitors to register for the board.

I'm already using the custom headers and footers mod (to insert Google Analytics and some link munging code) and I tried to add PHP. It appears that the stuff in the custom header/footer content is simply inserted inline with no coding interpretation. (The < ? php wound up being rendered on the page like text or HTML.)

Thanks for helping me get started on this.