You need a visa:
Some travelers may not be eligible to enter the United States visa free under the VWP. These include people who have been arrested, even if the arrest did not result in a criminal conviction, those with criminal records, (the Rehabilitation of Offenders Act does not apply to U.S. visa law...... Such travelers must apply for special restricted visas. If they attempt to travel without a visa, they may be refused entry into the United States.
http://www.usembassy.org.uk/cons_new/visa/niv/ vwp.html