In certain case, when you need to move your contact address into other email software or other computer because of hardware failure or unwanted virus infecting your computer. For that purpose its not necessary buying some certain software for back up.
Eventually your email software already have export / import option.

Here’s the scoop:

1. In Outlook, on the File menu, click Import and Export.
2. Click Export to a file, and then click Next.
3. Click Comma Separated Values (Windows), and then click Next.
4. In the folder list, click the Contacts folder, and then click Next.
5. Browse to the folder where you want to save the contacts as a .csv file.
6. Type a name for the exported file, and then click OK.
7. Click Next.
8. Click Finish.

That gives you a comma separate list of your Outlook Contacts. Transfer that to your new computer, then you can import them into your new version of Outlook with the following steps:

1. On the File menu, click Import and Export.
2. Click Import from another program or file, and then click Next.
3. In the list, click Comma Separated Values (Windows), and then click Next.
4. Click Browse, locate your file, and then click Next.
5. Click your Contacts folder or another folder that contains contacts, and then click Next.
6. In the list, click the file that contains your address list, and then click Map Custom Fields.

If those steps are too complicated for you, here’s the hint, just copy personal folder file from your old place into the new one.
Usually it was stored inside this folder:
C:\Documents and Settings\Administrator\Local Settings\Application Data\Microsoft\Outlook\xxx.pst
While for outlook express it was stored in:
C:\Documents and Settings\Administrator\Application Data\Microsoft\Address Book\xxx.wab

Thanks for Reading.