The One Search WPMU Plugin enables searching across all blogs in WPMU install. The project's goals are to create a search that:

• Installs easily
• Doesn't require core file hacking
• Updates automatically without a cron process
• Is compatible with other search plugins that use the default search box and template
• Plays well with potential post table updates
• Enables searching across all blogs

The current version of the WPMU search plugin can be downloaded from here: One Search WPMU Plugin Let us know how it works for you and how it can be improved!