The most excellent Writer Beware blog passes along the news that Noble Romance Publishing, which has garnered many complaints from writers, is shutting down--but the company's web site is still asking for submissions. Avoid.
They also note that Vanilla Heart Publishing has prompted many complaints from authors and a recent contract has many pitfalls for authors.
Last but not least, Iconic Publishing apparently has registered the copyright of some of their books in their own name, not the names of the authors, a violation of their contracts with the writers.
It can be very exciting to get an offer from a publisher, but don't sign anything in the heat of the moment. Do an online search using the name of the publisher and the name of the editor if you have that. Go past the first page of results--sometimes con artists will create fake web sites "reviewing" themselves with glowing praise, in order to push any negative reports to a later page.
If in doubt, check the Writer Beware publishers "Thumbs Down" list (they have one for agents as well).
Also do your research for any companies offering to help you self-publish. Make sure the rights to the book stay with you and that there are no hidden charges. If you think you might use a service to provide a cover image for your book, check samples of their work--I've seen terrible covers provided by such supposedly professional services.