Microsoft Outlook allows you to export data in a CSV (comma separated values) format which can then be imported.
  • Launch Outlook.
  • Select File | Import and Export....
  • Choose Export to a file and click Next.
  • Choose Comma Separated Values (Windows) and click Next.
  • Select the Contacts folder and click Next. You can select a different contacts folder if you have contacts stored in multiple folders.
  • Choose a filename for the exported data and click Next.
  • Click Finish. The file is now ready for import.