Import Outlook mails

Is there any method available to import outlook mails to apple mail. I am using lion Os and have office 2011 for mac in my system. I have appx important 5500 mails that i need to transfer in around 150 folders. I want to move these mails along with there folders intact. I this possible to move the mails as they are in folders to apple mail. Looking forward for answers/solutions.

Thank you for help.