The easiest way to keep your life simple and organized is through a centralized online address book. Yahoo! offers one of the Web’s best email and address books. You can save a lot of time by storing all of your valuable contact information online and downloading it to Microsoft Outlook when you want to have it on your desktop. This then allows you to synch it with your mobile phone or other devices that communicate with Outlook.
Log on to Yahoo! with your ID and password. Open your Yahoo! Address Book and click "Import/Export" in the upper-right corner.
Under the Export section, click the "Export Now" button next to "Microsoft Outlook."
A prompt window opens and gives you the option to save your Yahoo! Address Book as a .csv file. Click "Save to Disk." Clicl "OK" and the .csv file will be saved to your desktop.
Open Microsoft Outlook and open the "File" menu and select "Import and Export." Select "Import from another program or file" and click "Next."
Select "Comma Separated Values (Windows)" and click "Next."
Enter the location and name of the .csv file you wish to import (the one you saved in Step #3) or use the "Browse" button to select the file to import.
Select "Do not import duplicate items" or one of the other options that you desire and click "Next."
Select the "Contacts" folder and click "Next." Make sure to check the box next to the file you wish to impor and then click "Finish" to import your chosen file.