TechNet Blogs > Outlooking on Outlook - your answers are here > Free/Busy and Calendar Permissions in Outlook 2007 running against Exchange 2007 or later
Microsoft TechNet - Troubleshooting Free/Busy Information for Outlook 2007
UNC - Chapel Hill - Help & Support - [Exchange] How to Set Free/Busy Options in Outlook 2007, 2010, and 2011
Slipstick Systems - Publishing Free/Busy Information
SMTP25 - Exchange Free / Busy