The wp_insert_post action fires once a post has been saved. You have the ability to set it to only fire on new posts or on all save actions using the parameters. Please see Plugin_API/Action_Reference/save_post for more information. Keep in mind that this action is called both for actions in the admin as well as anytime the wp_insert_post() function is invoked.
This action can be replicated by creating a conditional in a save_post action that excludes certain post statuses.