Personal digital assistants, PDAs or palmtops as the name suggests are used as digital assistants where you can maintain your appointments, your calendar, your address book etc. It is a handheld device designed as personal organizers, which has become much more versatile over the years. A basic PDA usually includes a clock, date book, address book, task list, memo pad and a simple calculator. It can synchronize data with desktop, notebook and desk note computers.