Hi
This is an extract from the Help Files which may help you:

Import names and addresses into Outlook

1. Start Outlook and then, depending on the version you are using, do one of the following:

In Outlook 2010, click the File tab, click Open, and then click Import.
In Outlook 2007 and Outlook 2003, on the File menu, click Import and Export.

1. In the wizard that starts, click Import from another program or file, and then click Next.
2. In the Select file type to import from box, click Comma Separated Values (DOS), and then click Next.
3. Choose an option for dealing with duplicate names (default is Allow duplicates).
4. Click Browse, select the file you want to import, click OK, and then click Next.
5. Select the Contacts folder and click Next.
6. If you have more than just a column of contact names in your Excel file (for example, Address, Phone, City, etc.), you should map those columns from the file you are importing to Outlook fields. Otherwise, click Finish.