I have setup a couple multi-language sites now with the i18n module. One of them can be found here: http://butikk.tapirforlag.no

Just a fair warning: Setting up a complete store in Drupal/Übercart with the i18n module right now is a pain in the ass. Both because the i18n module itself has a lot of issues and because übercart itself really hasn't been written for this yet. So prepare to spend a lot of time hacking übercart core and tearing your hear out in the process There are still some issues I haven't been able to solve "in the right way" on the store i mentioned.

I have also setup some sites (non-übercart) with the localizer module and I definitely prefer that one over i18n.

I'm just looking forward to having core i18n+ support in Drupal 6 (and of course to having a übercart version that really support this stuff .

Best regards,
Thomas Kulvik
Ny Media AS
http://www.nymedia.no