I am reading an excellent article http://www.macosxautomation.com/applescript/features/system-prefs.html. The examples are good and easy to understand.
But now I have a question. The article only lists a few 'tell's, where can I find the complete references to those scriptable objects?
In your Applescript editor, you will find in the leftmost menu some reference named "Dictionaries". Keep in mind that those are present only if the application you want to pilot via applescript is open.
I use Satimage's Smile to develop/debug my applescripts, but the native editor is OK as well.
You'll also receive help reading articles from places like MacScripter, Satimage's site, AppleScript Support COmmunities... and SOF :)