“Truth in Caller ID Act of 2010” Passed In Congress, Makes Caller ID Spoofing Illegal.

Voice 2.0 IMS 2.0 has published about Congress passing the “Truth in Caller ID Act of 2010” (PDF) act
and making caller ID Spoofing an illegal act under certain circumstances, such as with the cases intent to defraud or deceive people. The law covers Legacy Telephony, VoIP IP Telephony, basically all telephony.
Caller ID Spoofing is, changing what someone will see on their caller ID display when they receive a phone call from a spoofed call. You can make a call to someone and make it appear to come from someone they know through caller id spoof.

Some of the legal caller id spoofing that are allowed are;

• Commercial answering-service bureaus which forward calls back out to a subscriber's cell phone, when both parties would prefer the CNID to display the original caller's information.
• Most calling-card companies display the Caller ID of the calling-card user to the called party.
• Business owners have been known to use Caller ID spoofing to display their business number on the Caller ID display when calling from outside the office (for example, on a mobile phone).

You can read more on the suject by by following the article on Voice 2.0 IMS 2.0