Add user info to AD account using a script

Hi, I need a little scripting help. I need to add the last 4 of each users SS# to thier account. Most probably I'll put it in the personal web page as that not populated for any users.

I can easly get an Excel spreadsheet with the users names and last 4. Not sure how to do this but I'm pretty sure it's possible.

Any help would be much appreciated.