Find it on drupal.org Drupal vCard Module
The vCard module adds a vCard download link to every users profile. This link makes it easy to add users on your Drupal site to your local address book.
Since we love microformats, there is also a theme function (theme_vcard) for displaying user data in the hCard format.
Bug reports and feature requests go to vCard Issue Queue
Licensed under the GNU General Public License, GPL v2.