I've done the following in the past:
1. Create a contact in Outlook.
2. Put data into all the fields that you intend to use
during the import. I often use First, Last, phone, etc
for the data for these cells to make them easily
recognizeable in Excel once the export is complete.
3. On the File Menu in Outlook start the import/export
wizard.
4. Export the contact to a windows CSV (comman seperated
value) file.
5. Open the file in Excel. You now have a spreadsheet of
the Outlook Contact fields and the correct order.
6. Add the Contact that you wish to import to this file.
DON'T change the column order or rename any column names.
7. Import the CSV file into Outlook using the
import/export wizard.
Also, you could simply save the existing Excel file as a
CSV and then import it. You'll have to manually map the
corresponding fields using this method. This is a little
more difficult, but not bad.
Chris