Are you looking for an IDE? Eclipse works fine, Geany is lighter ( www.geany.org/ ), bluefish is really fine.
If you are looking for a prototyping tool in PHP, I'd recommend Wordpress. You use PHP, learn a bit about the WP API, and then you create amazing websites in few minutes.
Netbeans has a well organized set of tool-bars, option panes and formatting and highlight styles, as well as a very "intelligent" (useful and helpful) code auto-complete and code assistance option.
Eclipse is a more customizable and extendible IDE which also has a quite well made code assistance option, but its default layout for PHP has way to many panes and tabs and tool-bars for different options that are not necessarily needed for PHP development, even when the PHP extension is used.
For education purposes, I'd stick to NetBeans for PHP.