This FTC press release provides an overview of their new 2002 National and State Trends in Fraud Identity Theft Report (in PDF). ID theft accounts for 43% of total complaints made, with fraud associated with Internet auctions accounting for 13% of complaints.
See also another new FTC report, ID Theft: When Bad Things Happen To Your Good Name, a step-by-step guide to prevent ID theft that also provides considerable useful documentation on services and resources available to those who are already victims of fraud.
For more information on this issue, the FTC participates in a program called Consumer Sentinel, along with state, federal and international law enforcement agencies and consumer advocacy groups, which produces, maintains and updates an ID theft and consumer fraud database. Some of the data is available to the public, such as fraud complaint and ID theft victims reported by state, as well as a chart of top complaint categories.