Take a look at this link
Export and import instructions are listed near the bottom of the page. (in your case the import functions are what you want to use. I'll list them here too)
How to import .pst file data into Outlook
Use the following steps to import a .pst) file into Outlook:
1. On the File menu, click Import And Export. If the menu item is not available, hover your pointer over the chevrons at the bottom of the menu, and then click Import and Export.
2. Click Import from another program or file., and then click Next.
3. Click Personal Folder File (.pst), and then click Next.
4. Type the path and the name of the .pst file that you want to import, and then click Next.
5. Select the folder that you want to import, or select the top of the hierarchy to import everything, and then click Finish.
Ferengi Rules of Acquistion:
Rule # 47 Don't trust a man wearing a better suit than your own.