Outlook Express / Windows Mail migration

Identify the best method of extracting the data from the Microsoft Windows Outlook Express and Microsoft Vista Mail client message stores. The data formats are not public, however there are many applications that exist that obviously understand the format (e.g. extractdbx). There is also an API that is available ([login to view URL]). My preference is for a solution that DOES NOT require either software to be installed on the desktop or the Outlook Express/Microsoft Vista Mail applications installed. i.e. It will operate on copies of the native message stores. The proposed solution should be specified and costed.