Managers of the public health insurance exchanges run by the U.S. Department of Health and Human Services (HHS) have started registering agents and brokers for 2015. The Centers for Medicare & Medicaid Services (CMS), an arm of HHS, oversees the HHS-run public exchanges. The Center for Consumer Information & Insurance Oversight (CCIIO), a division of CMS, manages day-to-day HHS exchange operations.
CCIIO has posted an explanation of the exchange producer registration process here. Producers can register to serve individuals only, small businesses only, or both individuals and small groups.