Thanks for the links Ryan. Looking through all of that, plus a few others, I took the dive. And in no time, I had it all working with Komodo IDE. Here's my simplified process that "just worked" for me.

How I got XDebug working with Komodo

Notes

This is only for a local install, local development. But the Komodo docs seem pretty good for getting it running on a remote server too.

• (I’m using MAMP from mamp.info)
• Start with Komodo
• Prefs -> Languages -> PHP -> Debugger config Wizard
• Choose PHP Installation: /Applications/MAMP/bin/php5/bin/php
• Choose PHP INI directory
  • to be copied: /Applications/MAMP/conf/php5/php.ini
  • make dir “debug” in /Applications/MAMP/conf/php5/debug
  • put debug version at: /Applications/MAMP/conf/php5/debug
• Use this extension directory: /Applications/MAMP/bin/php5/lib/php/extensions/no-debug-non-zts-20050922/
  • you might have to remove the trailing slash, to get past this page !!!

Now it is configured for IDE initiated debugging.

To allow the browser to initiate a debugging session:

• back up the original php.ini file
• copy /Applications/MAMP/conf/php5/debug/php.ini to /Applications/MAMP/conf/php5/php.ini
• restart apache
• In Komodo prefs, set Debugger -> Connection to port 9000.
• initiate from the browser like this:
  • http://localhost/?XDEBUGSESSIONSTART=komodo
  • http://drupal52dev2/?XDEBUGSESSIONSTART=komodo
  • or with the xdebug firefox extension