One of the main concerns of postcolonialism is the way in which the Western urban world is taken for the universal and anything other than that is exotic or strange. Joseph Conrad's "Heart of Darkness" is one example of a text that questions the othering of the outside world; this particular story (or novella or whatever you want to call it, at least in postcolonial readings) concludes that London itself, not some remote African jungle, is the heart of darkness. Bram Stoker's Dracula has also been famously re-interpreted by post-colonial theorists as a text showing reverse colonialism; some remote area somehow manages to assume control (or, at least, threatens to assume control) over the great city of London. Both works are from the late Victorian era, a period in which the British conquest of the world ("the sun never sets on the British empire" and all that) had finally become a subject of critique. Postcolonial criticism is an ongoing process, and I'm not familiar with the most recent trends, but I would suggest at the very least that you look at one or more of the foundational texts by Said (e.g. Orientalism) or the work of Ashcroft et al. (The Empire Writes Back).