There is no legal/license-related issues here.

To note php itself is licensed using a bsd style license, and so is
pear.

If you are thinking about selling whatever project you are creating and
if it's using GPL licensed software then there is a problem.

If you want to actually read the php license then here it is:
http://www.php.net/license/3_01.txt
There is nothing there even remotely close in it to do with preventing
php to be used with gpl licensed software.