CiviSMTP Service now has its own site:

http://civismtp.uas.coop/drupal

To sign up fill out the account application form at:

http://civismtp.uas.coop/drupal/civicrm/profile/create?force=1&gid=1

You can read more about the service and pricing here:

http://civismtp.uas.coop/drupal/node/3

Thank you!

-CiviSMTP Team