Public folders are the monthly theme for May on Microsoft Exchange Server TechCenter. Some good reading there!
Best Practices for Public Folders
Components of Public Folders in Exchange Server
If you can't get enough of public folder stuff, you might also want to mark May 23 in your calendar as I'll be delivering a Exchange Public Folder Internals Webcast then. I can promise you one busy Webcast with lots of information!
- Nino Bilic