Children are being targeted in a new scheme to combat illegal downloading.
The organisation which represents the US movie industry has released new software which lets parents check their kids' computers for illegal programs.
It lists all movie and music files on the hard drive. Parents then have the choice to remove the programs.
Movie piracy cost the industry £3.7bn in 2003, according to analysts, and legal action has been taken against people who have broken the rules.
"Many parents are concerned about what their children have downloaded and where they have downloaded it from," said a spokesman for the organisation, the Movie Association for America.
He praised legal movie sites, saying they were needed to "compete against operations that depend on stolen property to survive".