Derick Rethans, realizing that he wasn't ready to jump back into a full-time position just yet has decided to refocus his efforts on helping make PHP a better place with work on PECL extensions and on internals-related issues.
Instead I will be available to work on (custom) PHP extensions and internals related issues. Extensions are a great way around PHP's limitations and performance issues.
His first project is a QuickHash extension to interface with the popular StumbleUpon and works more efficiently by using more clearly defined data structures. There's no stable release yet, but keep an eye on the subversion repository for the latest enhancements.