California's new law SB-1411, calls for criminal penalities for impersonating someone online:
"any person who knowingly and without consent credibly impersonates another actual person through or on an Internet Web site or by other electronic means, as specified, for purposes of harming, intimidating, threatening, or defrauding another person is guilty of a misdemeanor."
Source: ZDNet: Analysis: California's Online Impersonation Law, Effective January 1