librarything announces the dev of a python tool for marc/z39 to xml.

http://www.librarything.com/thingology/2007/12/marcthing-simple-self-contain
ed-marc.php

gotta love this quote:

"What I hope is that this inspires allows people not in the library world
to do cool things with library data. It's sad that working with library data
 is such a hassle -- there are so many underused resources out there. I
 won't go too much into the technical problems with Z39.50 and MARC,
but I do have a recommendation for anybody involved in implementing a
 standard or protocol in the library world. Go down to your local bookstore
 and grab 3 random people browsing the programming books. If you can't
 explain the basic idea in 10 minutes, or they can't sit down and write some
 basic code to use it in an hour or two, you've failed. It doesn't matter
 how perfect it is on paper -- it's not going to get used by anybody outside
 the library world, and even in the library world, it will only be
 implemented poorly."

they are seeking feedback on use, so send tim spaulding your thoughts.