Well untested and NOT the most efficient code, but so that you can see output, maybe something like this.

You should really take the time though and read up on scripting so that you better understand what you're trying to do. There are also some great UDFS designed to do a lot of this for you.

Code:
For Each $UserOrGroupOrComputer in $ou 
  Dim $FullName
  $FullName = $UserOrGroupOrComputer.givenName + ' ' + $UserOrGroupOrComputer.SN
  'Full name for: ' + $UserOrGroupOrComputer.Name  + ' is: ' + $FullName
Next