Use home.php. There’s a tutorial here.
I just named index.php to index2.php (wordpress main page) and did the intro page..everything works.
I don’t understand the tutorial at http://www.chrisjdavis.org/2005/06/13/secrets-pt-3/. I just simply want to make an intro page for my website (powered by WordPress).
If you just want a different home page on your blog than what’s presented in the rest of it, you can follow skippy’s suggestion and set up a home.php template in your theme. Simplest method for this is to make a copy of the theme’s index.php and edit as desired. More info on theme templates and template hierarchy can be found here:
http://codex.wordpress.org/Template_Hierarchy
Beyond that it would help to know exactly what you expect from an “intro page”.