In Outlook 2010:

1. Click the File tab.
2. Click Open and then click Open Outlook Data File.
3. Navigate to the .pst file to import and then click Ok.

In Outlook 2007:

1. On the File menu, point to Open, and then click Outlook Data File.
2. Click the .pst file that you want to open, and then click Ok.

The name of the folder that is associated with the data file appears in the Folder List. To view the Folder List, on the Go menu, click Folder List. By default, the folder will be called Personal Folders.