At my job, we are currently using a product called 'Correct Address' (how creative), from a company called Intelligent Search Technology Ltd.

It has a very rudimentary perl interface, which a co-worker of mine has written a decent layer on top of. I believe that he is refining it as i type. We've been using it for about 2 years now, and it serves its purpose.

My only other experience with address correction software is a product called AccuMail from a company called Datasoft. They did not have a perl interface when we used it, and their support was less than great.

A word of warning regarding any of these products that i've seen. They assume that you have pretty clean addresses to begin with, if your addresses have issues, you'll need to write your own code to get your addresses into a halfway decent format, before the CASS software will handle the addresses properly.

Again it all depends on what you begin with, and what you want to do with it.