US Department of the Treasury Financial Crimes Enforcement Network - FinCEN
http://www.fincen.gov/financial_institutions/msb/
Businesses offering check cashing, money orders, travelers checks, money transfers, currency dealing or exchange, and pre-paid access (formerly stored value) products are Money Services Businesses and are subject to Bank Secrecy Act requirements.
Key Facts
With few exceptions, each money services business must register with the Department of the Treasury by filing a Registration of Money Service Business with FinCEN.
Additional Information
As of April 1, 2013, financial institutions must use the new FinCEN reports, which are available only electronically via:
the BSA E-Filing System
Who it affects
Businesses offering check cashing, money orders, travelers checks, money transfers, currency dealing or exchange, and pre-paid access products.
Wikipedia Entry
http://en.wikipedia.org/wiki/Money_services_business