Dreamweaver is a poor IDE for coding PHP, Netbeans or Eclipse are far better. PhpDesigner isn't bad either.
Here's my 2 pence review
CodeIgniter: easy to learn, but based on PHP4. May lack power for more complex jobs. Great documentation - best starting point for beginner.
Kohana: basically an OOP/PHP5 version of CodeIgniter, with less documentation.
CakePHP: forces convention over configuration. What that means is that it offers you one way to skin a cat so you don't get confused.
Zend: The antithesis of Cake - you can configure this all over the place, and it can be very confusing. Documentation can sometimes be confusing.
Symfony: uses a lot of configuration again, but is recognised by the enterprise community.