I saw this site linked here a while back, it's actually pretty good, http://www.nationalismproject.org/what.htm. The names on the left hand side are a pretty good "who's who" in the big nationalism dates from the last couple of decades.

anderson is pretty seminal in the field still. Depends on what kind of books or work you're looking for, but his main contribution to history, as opposed to sociology or political science, is to retroactively look at past societies, or the histories of current societies or states, and begin to ascribe to them an identity that they themselves may have prefered, albeit unknowingly.

in that regard, recent histories of albania, the czechs, the caucasian minorities, central asian peoples, nomads of the russian steppe - all pull from thoughts put forward by anderson's idea that a people form themselves into an imagined community and thus from that are we split, consciously or otherwise, into segments of society, even if that society happens to be a state, federation or empire which differs significantly from the minority identities within.

eric hobsbawm is probably the most well known proponent of nationalist history, but has a decided leftist slant. he's still good to read for an idea of the way that nationalism affected the history of the 19th century.