Hi Jeffturn - not sure that you can accomplish ALL of your goals from the iPad alone?
First, you need to get the CSV file onto the iPad and into a program that will allow you to view and manipulate the information; on my iPad 2, I have Numbers & GoodReader which can read those files, Numbers being the iPad equivalent of Excel (so even an *.xls extension would work); the files could be transferred 'wired' or 'wireless' (e.g. I would probably use Dropbox).
Second, once on the iPad and in a program that can display the data, are functions available to format that data into a 'mail label'? And finally, is the iPad capable of 'wireless' printing to mail labels? The first issue is easy, the latter ones are more difficult in my mind, at least w/ the apps that are on my iPad.
But I'll be quite curious if there is an answer using the iPad alone, and hopefully others who may have had this same issue will 'chime in' - good luck!