jedit is an amazing Java/php/text processor. It comes with a large number of installable plug-ins, is capable of color-coding syntax for java, php, HTML, perl, and other languages, stores each open document on a tabbed window, and has an aqua-ish appearance theme! And, best of all, it's open source and totally free. You can read more about it on the
jedit home page.
Kris Kopicki has created a pre-compiled package version of jedit for OS X PB, and I've been using it for a day or so. It's written in Java, and runs fine on the PB (perhaps it's a tick slow, but not enough to bother me). You can find it on Kris' page
right here.
Highly recommended if you do coding of any sort, or just want to see a slick Cocoa/Java app.