Othman Ouahbi has a very nice example on his blog on creating automatic updating select-boxes with Ajax.
If you change the first select-box, it updates the next selectbox accordingly.

svn had 2 very nice items:
The top 5 red flags of software development:

As cakebaker states:

The use of "Model/field" in the formhelper has been deprecated in CakePHP 1.2. In CakePHP 1.1 you would call:

$form->input('Post/title');

Ahsanul Bari created a nice list of links to articles on the use of Ajax in CakePHP. Some of the parts covered are:

• Getting Started
• AutoComplete
• Ajax Redirect
• Ajax Validation
• Encoding
• Ajax Uploader

Previously (in CakePHP 1.1) it was best to add an exit or return after you redirect method like:

$this->redirect('controller/action');
exit();