The System.Web.UI.WebControls.CreateUserWizard class will send an e-mail message confirming that a new Web site account has been created when the CreateUserWizard.MailDefinition property defines an e-mail message to send.
Because the e-mail message only has automatic replacement fields for the user name and password fields, you can use the CreateUserWizard.SendingMail event to modify the e-mail message before it is sent to the new user.
For more information about handling events, see Consuming Events.