A major ticket seller for concerts and sporting events is going ticketless. Ticketmaster is introducing paperless tickets. Customers will be able to present a valid I.D. and the credit card they used to purchase the tickets to gain entry to an event. The new system eliminates the need to download tickets, get them by mail or pick them up at will-call. The new paperless ticket program is available through the Ticketmaster Web site and its charge-by-phone system.