On the New Media Campaigns site today they've posted an interview they did with Josh Lockhart, the lead developer behind the Slim PHP framework project. In it they talk some about his own experience and the framework, both past and future plans.

We have long been proponents of team members spending a portion of their time at NMC to work on side projects they're passionate about. The policy has been a great success, and we make many of the projects available to other developers, designers, and marketers. [...] One of the most successful projects is the Slim framework for PHP built by Josh. Josh noticed a void in PHP and decided to fill it by building his own framework. He collaborated not only with NMC'ers but also with programmers around the world to build Slim.

They start by getting to know Josh a bit, talking about his background in PHP and the origins of the Slim framework. They move on to talk specifically about the framework and what originally pushed him to create it. The interview also talks about how his work has affected both the community as a whole and his own current work.

He also offers two pieces of advice for beginning PHP developers:

For developers new to PHP, I encourage you to spend more time learning the HTTP protocol rather than focus too much on learning the PHP language. Obviously, you have to know PHP, but don't spend all your time doing so. [...] Also, join your local PHP User Group. Believe it or not, there are likely lots of fellow PHP developers nearby. If not, you can join the online Nomad PHP User Group.