I just read about this today over at YAHighway, and since this is a horrific scam I thought I'd post the info as well as my comment here, too.
From Publishers Lunch:
Writers House has learned that a series of fake emails claiming to be from WH agent Jodi Reamer have been circulating to self-published authors this week. "These emails, which contain a number of false statements, have not in fact come from Jodi Reamer and should thus be disregarded." One easy "tell": they advise that any e-mail from a non-Writers House address "expressing interest in representation is counterfeit."
I've been a client of Writers House for twelve years. When I queried WH back in 1998, I had a personal rec from a Big Name Author and a two-book contract offer from a major publisher in hand. My agent (Robin Rue) did not sign me instantly; she asked to see the full manuscripts plus other samples of my work, and then she called me to talk about my career goals. Then she had to think about it. The whole thing took about three weeks.
While some agencies or agents do move faster, and occasionally a promising writer will end up having agents fighting over them, when it comes to signing with a prestigious agency it generally does require some time.