This article provides instructions for setting up Komodo Edit and code completion for joomla.
Once you have downloaded the latest version of Joomla from the link above you'll want to put it somewhere on your drive where it won't get lost or deleted by accident. Unpack the Joomla file you just downloaded to this location.
Start the Komodo Edit software you just downloaded and installed and in the menu at the top you will see a menu option titled Edit. Go to Edit -> Preferences and a dialog will appear. Find Languages in the list on the left, expand it and you will see another list of languages, click PHP in the sublist.
On the right of the screen under PHP Directories you can specify any directories that you want Komodo to use for autocomplete and calltips. Komodo will recursibely scan these directories for information.
Press the green plus icon to add a new directory and point it at the Joomla package you unzipped and placed somewhere safe. Mine is in "C:\joomla\joomla2_5\Joomla_2.5.4-Stable-Full_Package" press okay and the editor will add the all the joomla code to it's database and you'll have code completion as soon as it's done scanning.
Now you're ready to start coding. Type "JFactory::" into your new php extension and Komodo will list all the methods available to JFactory.