If you know a little PHP and understand the basics of Joomla, then you can easily create a simple module for your site.  I've created a video tutorial that shows how I created my Twitter module.  I decided to put it somewhere where tutorials belong, and thanks to Brad at Joomla Tutorials for helping me out with posting it.

Video Tutorial on Creating a Joomla! Module

Please check it out and let me know what other topics you would like to see videos on, particularly in regards to development for Joomla!

Also, if you haven't, you should follow me on Twitter @gnomeontherun.