In a new blog entry Philip Olson takes a look back at the "brief history" of the PHP logo and how its evolved over the years the language has been around.
PHP 4.0.0 added main/logo.h which contains the logos themselves (as text (a bunch of numbers (magic))) so I checked out every version of this file from CVS, parsed them to create the images, sorted by version/size, then wrote this blog post.
When the language started out there wasn't much in the way of a logo until PHP3 came around. Philip shows some of these early prototypes (most of which look nothing like the familiar purple oval of today). Things evolved with PHP4 and jokes were even played with the area inside the shape - everything from developers and dogs to bunnies showed up at different times of year or with special URLs.