Thanks to Neil Jefferies for a link to this article in The Register, which tells us that MS has begun two open source projects that will make it possible for developers to create tools to ‘browse, read and extract emails, calendar, contacts and events information’ which live in MS Outlook’s .pst file format. These tools are the PST Data Structure View Tool and the PST File Format SDK, and both are to be Apache-licensed.
Last year Microsoft said that they would publish the format specifications for personal store files (pst) – formats used to store data from Outlook products, including email, contacts and diary appointments. You can find them at MSDN here: http://msdn.microsoft.com/en-us/library/ff387869.aspx. There is also format information for other Office products: http://msdn.microsoft.com/en-us/library/cc313118.aspx.
Related sites of interest include Microsoft’s interoperability pages, such as their ‘open specification promise‘ and Microsoft’s interoperability blog.