Today, PHPHead.com has links to several of the PHP IDEs that are out there these days. Rather than re-linking to all of them, just visit the site and take a look for yourself.
Also, on the heels of PHP.net's redesign, the NewbieNetwork is working on a redesign for their site too. They want to slim down a bit from PHPNuke and get more focus on what they want to do with their interface. Hmm...doesnt sound like too bad of an idea...