Transferring Email and Contacts from Outlook Express (PC), to Apple Mail (Mac):
*requires that Outlook (MS Office) is installed.
Emails:
1) Install Outlook (can use trial version), if not already installed.
2) Import emails into Outlook from Outlook Express.
3) Use O2M software to export .dbx files to .mbox.
4) Transfer .mbox files to Mac computer.
5) Import .mbox files using Apple Mail.
Contacts:
1) Export to Outlook.
2) Export to .csv.
3) Transfer.
4) Import using Apple Contacts.
Moving Email from PC Outlook to Apple Mail – Mac Guides
http://guides.macrumors.com/Moving_Email_from_PC_Outlook_to_Apple_Mail