The PHP::Impact blog has pointed out a new bit of software that can help you get your social networking application "up and running in minutes" - Symfonians.
Symfonians is an open source (CC-BY-SA 3.0 licensed) project-centric social networking web application written in PHP5 and based on the Symfony framework (1.0 stable version is used). The code has been extracted from the Symfonians.net application.
Lots of features are included like an applications directory, a job offers catalog, weblog management, maps and geolocation and support for microformats. Check out the project's site for prerequisites and quick install information (via subversion).