Physician-blogger "911DOC" illustrates the difference that the EMTALA law has had on physician-to-physician consults.
EMTALA stands for "Emergency Medical Treatment and Active Labor Act", and it is a federal law that mandates that in most circumstances hospitals treat patients that come into emergency rooms regardless of ability to pay. Additional information and specifics can be found at:
<http://www.emtala.com/faq.htm>
Rather than quoting 911DOC's piece verbatim, I encourage you to read the whole thing.
(Via KevinMD.)