The PHP.net site has made the official announcement of the PHP projects involved with this year's Google Summer of Code:

The PHP team is once again proud to participate in the Google Summer of Code. Seven students will "flip bits instead of burgers" this summer:

On the list this year are:

• LiveDocs - mentor Michael Wallner, student Hannes Magnusson
• The PHP Interpreter - mentor Derick Rethans, student David Wang
• XDebug - mentor Derick Rethans, student Adam Harvey
• Doctrine - mentor Lukas Smith, student Konsta Vesterinen
• PHPUnit - mentor Sebastian Bergmann, student Mike Lewis
• MDB2_Schema - mentor Lukas Smith, student Igor Feghali
• Jaws - mentor David Coallier, student Nicolas Bérard-Nault

Also, be sure to check out some of the other organizations and students participating on the Summer of Code website.