Google announced the project lists for Summer Of Code 2008. Some of the more interesting projects from my perspective:

Adium

• Data Detectors for Adium

Dojo Foundation

• Native cryptography API for Google Gears
• Dojo-Charting improvements
• Dojo GFX Enhancement

FFmpeg

• AAC-LC Encoder
• MLP/TrueHD encoder
• Apple Lossless Encoder for FFmpeg

Gallery

• Facebook / Flickr Style Image Region Based Tagging

Inkscape

• SVG Fonts

Joomla!

• Multi-DB support, and Database abstraction layer implementation for Joomla!

The Mozilla Project

• Natural language parsing for automatic calendar event creation
• Powerful search engine for SUMO
• Support OpenID as an account login in Bugzilla
• Google Contacts Extension for Thunderbird

MySQL

• Streaming Enabled MySQL Driver for PHP
• MySQL query analyzing tool
• New in-memory storage engine
• Memcached for Query Cache

PHP

• Implement Unicode into PHP 6

Pidgin

• Master password support for pidgin

WebKit

• WebForms 2.0 Support
• Improving and Extending WebKit Inspector

WordPress

• WP-storage
• Integrated Caching Solution
• Improving the search system