On Friday, Lost in Greenwood Heights posted a warning on Brooklynian.com about IDT doing aggressive recruitment in Greenwood Heights and other Brooklyn neighborhoods. The seventh post in the thread about IDT gives some specific information about a call from a woman who claimed to be from National Grid but couldn't give any particular information.
Today, GowanusLounge adds (thanks to a neighborhood listserve) that a company called Accent Energy has been making calls about wind energy and promised "rebates." Check out the link for the full story. They also have links to the details from last week.
Basically, if you receive a call or visit from someone about energy savings (obviously a big deal right now!), be wary and suspicious and careful with your personal and account information.