unauthorized use of computers and networks

U.S.A warns against unsecured wireless internet
Wireless Internet access can free you from the confines of cords, but not from the need for security. Without taking the proper precautions, it''''s easy for others to use your wireless network connection to access the Internet, or even to access the information on your own computer. The Federal Trade Commission is introducing a new section of OnGuard Online at www.OnGuardOnline.gov/wireless to teach computer users how to protect their personal wireless network connections - and the computers on them - from unauthorized use. The information also is available in Spanish at www.AlertaenLinea.gov/inalambrico.
The FTC cautions that allowing strangers to "piggyback" on a personal wireless network actually could be risky. Hackers can take advantage of an unprotected wireless connection to access information on any personal computers on that network. And if an unauthorized person uses your network to commit a crime or send spam, the activity can be traced back to your account.