The Electronic Transaction Association (ETA) has a good write up on the Merchant Card Information provisions that are part of the American Housing Rescue and Foreclosure Prevention Act of 2008 (HR3221)
“The major outlines of the requirement are clear: Acquirers must report to the IRS the aggregate dollar amounts of credit and debit card transactions for each merchant that has more than $20,000 in transactions and more than 200 transactions per year. Reporting will have to be done by taxpayer identification number (TIN). In certain cases, acquirers may also have to subject merchants to backup withholding.”
Looks like the burden of this is mostly on Third Party Processors and Acquring Banks who settle transactions directly with the Card Brands, also note that cards types also include ACH, Paypal. and goes into effect at the end of 2010.