Need to maintain a web site or web application in multiple languages and localizations? You might be interested in Yahoo's r3. In case you missed the PHP Architect cover story from June, r3 is a Yahoo! open source project (on SourceForge) designed to help developers of web applications customize and translate their web pages and templates for different languages, markets, and uses.
In the spirit of "eat your own dog food," Yahoo! is using r3 internally with the Symfony framework as well as with standalone pages. Though still somewhat nascent, r3 is getting lots of love thanks to project manager Matt Zandstra along with business lead Fergus Sullivan, and co-conspirators Steve Webster, Bill Hails, Robin Baker, Ludovic Dreux, Chris Kaminski and Stone Li. Written in PHP and originally released as a command-line tool, r3 will soon have a spiffy new GUI thanks to this team. Stay tuned for future releases.
A completely separate open source project (which made the September cover of PHP Architect magazine) is Stickleback. Stickleback is a general purpose plug-in framework that you can use to add a plugin API to existing PHP web applications. Stickleback ships with tools for creating pluggable CLIs and GUIs. r3 uses Stickleback as its plugin engine so developers can write plugins to extend r3's functionality.
You can find out more about r3 and Stickleback, including some tutorials, at Matt Zandstra's unofficial blog. You can download the latest versions of r3 and Stickleback from their Sourceforge project pages: r3 Sourceforge Project - Stickleback Sourceforge Project