[FX.php List] Curious: include-page naming conventions

[Joel Shapiro]

Hey All

I've been working a bit in a number of other people's php projects  
lately, and have come across a couple naming conventions for include  
pages that I'd never noticed before:

page.inc.php  & _page.php

Do people here use these (or other) conventions?  Will an extra dot in  
a file name *never* cause problems?

Other thoughts on the topic?

-Joel