The information on this page is likely to be outdated, since I no longer deal with deploying and operating large-scale messaging systems.
- How Exchange's Autodiscover Works With Mail.app
- Zarafa, another company doing a clone stack.
- OpenChange, an attempt at re-implementing the necessary protocols in a portable fashion, supplying MAPI libraries, Wireshark dissectors, the works.
- Brutus, a library and proxy connector to access Exchange servers.
- PostPath supplies a MAPI transport to emulate Exchange-like functionality on UNIX servers
- MS Exchange Blog
- The Exchange Project - Syncing Exchange to iCal and back
- Slipstick Systems - simply the best Exchange and Outlook site you'll ever find.
- Accessing an Exchange mailbox using WebDAV
- ASP.NET samples for WebDAV access.