I recently came across MoyoSoft's Java Outlook Connector. I haven't tried it myself, but if you've got a Java project that could benefit from accessing all that lovely data held in Outlook, it looks like a perfect fit. It lets you read messages, calendar entries, contacts and send mails, pretty much everything that's exposed by Outlook's native OOM API.
They offer a free evaluation version, code examples and a demo application if you want to check it out for yourself. Even if you've got a web-based service, this looks like a great way to create a downloadable app to import contact information from Outlook.