Set the inital number of empty values for a cck multi-value field
Unfortunately there is no way to do this without altering the module code of CCK. 

There have been a few patches created that will allow you to set the number of fields initially shown and let you choose how many more to add when click the "Add another" button. However, this feature is not available in the core of Drupal 7 which may be a problem if you choose to upgrade.

Patch created for CCK 2: http://drupal.org/node/530828#comment-3397196

Patch created for CCK 3: http://drupal.org/node/841914#comment-3209072