Piggybacking refers to gaining access to a wireless Internet connection by bringing your laptop computer within the range of another’s wireless connection, and using that service without the subscriber’s explicit permission.
Check below scenario – you live in a multi storied building and your apartment is in the 3rd floor. Someone from the 2nd floor always connects to your wireless network and browses the web, downloads files and you have to pay for the extra usage bills.
Basic mechanism of Piggybacking
More Info Abt Piggybacking_IA [ Internet Access]
http://en.wikipedia.org/wiki/Piggybacking_%28Internet_access%29
Plese elaborate it whether any software available to do and so.......