Drupal substracts 2 hours from the CCK date field when saving. Why?
In Drupal 6 at least, you would go to admin/settings/date-time to check the default timezone of Drupal. I'd check to see if that's set correctly.  If it is, then you have to check if user configurable timezones are enabled, and if so, check what you or the logged in user has set in his/her account against all of the above.