Import Mozilla Address Book into webmail:
The first step in importing your Mozilla address book into webmail is to export it from Mozilla in a format that webmail will understand. Open up your Mozilla address book, click on the Tools menu, and select "Export":
When the "Save as" box comes up, make sure that the Save as type drop-down is set to LDIF, and save the file to a location where you will be able to find it easily.
Now from webmail, select the Address Book tab, and click on Import/Export:
Click on the Browse button and navigate to the file that you exported from Mozilla.
Now click import and your address book will be imported.