The reading app was (I believe) Mobipocket, but development stopped after v4.8 was released. That's okay; it should still be a pretty capable reading app. You can actually still buy apps for the eBookMan, and that will also stop on April 30th.
I had discovered that this ereader was still being sold by Ectaco a couple years ago, but at the time I thought that was old stock or refurbished. Franklin never adequately promoted or supported this eReader, so it is something of a surprise that it's still being sold as new.
Does anyone still use one of these things?