Create a workflow rule that emails record owner when a new lead is created
Use the API to add a lead needing approval (as in a contact form on a web site) which lands in the Lead Approval area
Select a lead to approve
Click {Change Owner and Approve Lead}
The workflow rule is executed before the lead changes owner, which means the wrong user gets the email notification of a new lead. Old user gets email notification, then lead changes to new owner, who has no idea the lead was added unless the old owner forwards the workflow email notification.