SharePoint column permission extends sharepoint default permission by adding column permission. This function is greatly needed by users, and now setting column level permission becomes quite easy.  SharePoint column permission can:

Assign read or edit permissions to columns

Make columns non-editable or invisble in edit or display form

Make view invisible to those who have no read permissions on columns in the view

You can find more information in http://www.sharepointboost.com/columnpermission.html

SharePoint column permission, sharepoint permission, permission, sharepoint webpart, sharepoint service, sharepoint item, item, column, sharepoint 2007