Here’s what I did:

1. Install Marc Liyanage’s PHP5 package for Apache 1.3.x
2. Mod your path defaults
# sudo su -
# cd /usr/bin
# mv php php4
# mv phpize phpize4
# mv php-config php-config4
# ln -s /usr/local/php5/bin/php php
# ln -s /usr/local/php5/bin/phpize phpize
# ln -s /usr/local/php5/bin/php-config php-config
3. Get xdebug
http://www.xdebug.org/download.php
4. Install xdebug per instructions found here:
http://www.entropy.ch/phpBB2/viewtopic.php?t=847&view=next
%sudo ln -s /usr/bin/glibtoolize /usr/local/bin/llibtoolize
# gzip -dc xdebug*.tar.gz | tar xvf -
# cd xdebug*/
# /usr/local/php/bin/phpize
# ./configure --enable-xdebug
# make install (mine copied to /usr/lib/php/extensions/no-debug-non-zts-20020429/)
# vi php.ini
(appended to end of file:)
zend_extension=/usr/lib/php/extensions/no-debug-non-zts-20020429/xdebug.so
# apachectl restart

Good luck!