The long and short of it is that a few online financial institutions (Neteller, eCheck, Citadel and Instadebit) have opted out of the US market as an encompassing response to US legislation passed in late 2006.
Due to restrictions on online sports betting in the U.S. (which under the Wire Act has legal consequences), NETELLER, eCheck, Citadel and Instadebit have withdrawn their services from the US market effective immediately.