Email migration from Mac Mail to Outlook 2011 for Mac
For transferring all your apple mail items in to Outlook 2011, there is a need of robust data format conversion process. This step helps you to migrate from one mail client to another. In this reference, an apple mail to Outlook 2011 converter is desired to fulfill to requirement. However, you can accomplish this task by manual method also but it faces some pitfalls.

So, check a review of required converter that i found as a resource on web mentioned below:
http://download.cnet.com/Mail-Exporter-Pro/3000-2369_4-75877193.html