Right after I sent an e-query to an agent, an ad for the Whitmore Publishing Company appeared in my Gmail courtesy of Google adsense's witchcraft. Whitmore, it turns out, was soliciting submissions (in all genres, no less). I took a quick look at SFWA's Writer Beware Blog, and lo, my suspicions were correct: Whitmore shows up. A little poking around and it turns out Whitmore is an imprint of Dorrance, a big vanity house.
Just something to keep in mind if anyone who's reading this is a writer: publishers and agents are absolutely swamped, all of the time, and between the Writer's Market and Google, they'll never run out of potential clients. Anyone who's actively soliciting manuscripts is running a business model where they get paid the more books they publish, rather than the more books they sell. This runs the gamut from print-on-demand publishers (who don't generally try to hide what they are) to vanity presses (which from what I've seen, are usually pretty shady operators--they provide services paid for, but they're real cagey about the fact that no bookstore will ever carry a book from a vanity press) to outright scams.