This is an excellent PDF provided to me by a friend who runs the National Money Transmitter Association in the USA.
Briefly for those who don't know, with few exceptions, each money services business (MSB) must register with the Department of the Treasury and follow certain KYC and AML guidelines and requirements. Note that failure to register when required to do so or obtain necessary state licensed, can lead to jail time. Most states require money services businesses operating within their territory to be licensed with the state banking department. Note that many states also require registration of foreign MSBs that transact with their residents. For example, money transmitters with no physical presence in New York that transact with residents of New York must be licensed in the State of New York
This is one of the largest obstacles Bitcoin companies are currently facing to legally operate in the USA.
It's extremely difficult for MSB's and MTB's to get bank accounts as well.
The National Money Transmitter Association put together the following amazing document which outlines it state by state.
The second attachment is a white paper on Government Oversight of Non-Bank Financial institutions In the United States and Why Change is Urgently Needed. A White Paper Prepared by The National Money Transmitters Association David Landsman, Executive Director Originally Published September 12, 2012.
I've done extensive research and have experience in this field, feel free to ask any questions!