Hyper Cache plugin by satollo and momo360modena is a new cache system for WordPress, specifically written for people which have their blogs on low resources hosting provider (cpu and mysql). It works even with hosting based on Microsoft IIS (just tuning the configuration). It has three invalidation method: all the cache, single post based and nothing but with control on home and archive pages invalidation.
It has not yet tested for multisite configuration (WordPress 3.0 feature).
Some features:
compatible with the plugin wp-pda which enables a blog to be accessible from mobile devices
manages (both) plain and gzip compressed pages
autoclean system to reduce the disk usage
404 caching
redirects caching
easy to configure
Global Translator compatibility
Last Modified http header compatibility with 304 responses
compressed storage to reduce the disk space usage
agents, urls and cookies based rejection configurable
easy to integrated with other plugins
Plugin homepage: http://www.satollo.net/plugins/hyper-cache