You can import contact lists and address books that are saved in a comma-separated (.csv) text file format. Import is available from your Options>Import/Export tab.
To import a contact list:
From the Options tab, click the Import/Export tab.
In the Import section, select the type as Contacts.
In the drop-down next to Contacts, select the type of contact file that is being imported:
Outlook 2000 contacts
Outlook 2003 contacts
Contact lists from different accounts may not display contact information in the same order. Picking the correct type of contact file that is being imported identifies the order of the fields so that the information displays correctly in your Address Book.
Browse to locate the contact .csv file to import.
Click Import. In the Choose Address Book dialog either select an existing address book to add the contacts or create a new address book to import the file.
Click OK. The content of the contacts file is imported.