Thanks to a Gmail ad I recently discovered Moonrug Software. They offer a Java-based library that uses the MAPI network protocol to interface with any Exchange server. This is the same way that Outlook connects to Exchange, so it has the potential to support everything Outlook has access to, including calendar and contact information. This makes it a lot more comprehensive than basic email protocols like IMAP.
I’ve exchanged a few emails with Moonrug’s founder, and they’re still rolling out their full package, but they have recently released a sample demonstrating synchronization with Exchange. It’s good to see someone figuring out a cornerstone of the Exchange connectivity puzzle. Traditionally Microsoft has tried to maintain a competitive advantage by keeping it’s mail ecosystem as closed as possible. In theory that’s changing with the new Windows Open Protocols initiative. In practice they’ve not yet got around to releasing the really juicy details of things like the MAPI network protocol, so you’re stuck trying to reverse engineer them instead. Moonrug have been working on that approach for the last couple of years, long before the protocol initiative was announced.
Their product should be a great alternative to trying to do the same yourself, helping to open up the Exchange world to some real innovations.