So over the past well, 7 months from the #joomla channel on IRC on irc.freenode.net I keep seeing people almost daily asking about learning how to develope for Joomla 1.5 (even some 1.0 people that we tell not to even consider 1.0 as its coming to the EOL) so tonight or this morning I decided to write a little article on learning to develope for any aspect of joomla
PLEASE NOTE: If you noticed anything important that I have left out please email me or if you want to add to this, As I am NOT a programmer, I am just taking all the links and the information I have learned from talking to programmers and helping adapt a PHP programmer into a PHP Programmer who can code a Joomla Component.

First off, I think you should have a understanding on the joomla frame work, you should never hack the core to do what you want, if you fill its something missing or its a bug in Joomla dont just submit a but report, all the people who work on 1.5.x release do not get paid by the hour, or by the project... They voluntear, try to fix the bug/feature flaw yourself and submit the patch to the proper place.
Second I am not a programmer, Im a hacker, i take code and modify it a bit, I have programmers who work for me and are way faster then me and I have no desire in becoming them.

Framework (MVC)
1.5 Native
Templates
Components
Modules
Plugins