Microsoft made available the "PST File Format SDK," which provides a cross-platform C++ library for reading files using the Outlook Personal Folders File Format (.pst) Structure Specification.
"If you're a developer building a solution that accesses Outlook Data Files (.pst), this SDK provides a source code library to jumpstart your application development. Otherwise, if you use Outlook in a business or organization setting, this announcement helps developers create solutions for email archiving, backup, and legal discovery. With the PST File Format SDK, Outlook doesn't have to be installed on a computer for applications to access Outlook Data Files (.pst)," noted Microsoft.
Download: PST File Format SDK