What is MRBS?
MRBS is a free, GPL, web application using PHP and MySQL/pgsql for booking meeting rooms. It's similar in concept to Netscape Calendar, but much cheaper!

Some features:
Web/Intranet based - Available from any workstation through a Browser
Simple to follow, Web based options and intuitive presentation
Flexible Repeating Bookings
Authentication with your existing user database (eg Netware, NT Domain, NIS etc.)
Ensures that conflicting entries cannot be entered
Reporting option
Selectable DAY / WEEK / MONTH views
Multiple auth levels (read-only, user, admin)
Multiple languages supported (translated to Catalan, Czech, Chinese, Danish, Dutch, Finnish, French, German, Greek, Italian, Japanese, Korean, Norwegian, Portuguese, Slovenian, Spanish, Swedish, Turkish)
Stable and in use at many organizations
MySQL and Postgres support

Demo
There is a demonstration version of MRBS installed here. Please try not to break it too badly!