ubercart uses it's own system to store addresses, sometimes however you need the address also outside of the e-shop
I just got this module into Drupal.org.
See http://drupal.org/project/uc_addresses.
I also added a page on this site: http://www.ubercart.org/contrib/4872.
The code in CVS is pretty much the same as the last archive posted here except that I added a lot of check_plain() calls for security and tweaked a few things to match the Drupal requirements.
The uc_addresses module adds support for one or more addresses in the user's profile.The Ubercart order process is altered so that users select delivery and billing addresses from their collection of addresses rather than from previous orders. You can ask the module to automatically fill in the billing and/or the delivery address with the user's default address. Any new addresses entered during the order process are automatically added to the user's list.