I understand what you want to do and you can import these by opening the address book and going file>import & export. Then select import from file, select CSV (Windows), and then navigate to the file.
However. I prefer to do this another way. I have to communicate with 180 Rugby clubs and some 300+ referees. Basic information that includes for example the information we hold on our web based database. (They can update it using their own logins at any time) I am supplied an Excel spreadsheet with each individual, information fields and e-mail address from our webmaster. Because the information can change on a daily basis I couldn`t possibly keep track of it myself.This week I am reminding all the clubs that we need accurate info on club contacts, (Secretary, Fixture secretary etc)
I do this by creating a mail merge document in Word that is linked to the current excel file supplied. I can then tell them what we have on our database for all their officers and their contact details. At the end of the merge I merge to e-mail. Check if this facility is available in your version of Office. Post back if you need more help. It`s a nightmare first time through!