I am working on several novels and stories set in the Culture universe created by Iain M. Banks. This task is tractable only because so many kind people had contributed to descriptions and annotations of the novels.
So, here I have gathered together a collection of resources I have found useful in my self-imposed tasks.
http://www.iain-banks.net/: the official web site for Iain M. Banks.
There is a UK-specific version of the site at http://www.iain-banks.net/uk/.
There are a great many references to Iain M. Banks work and the Culture in Wikipedia. A selection of the articles follows.
http://en.wikipedia.org/wiki/Iain_Banks: Wikipedia page for Iain M. Banks.
http://en.wikipedia.org/wiki/The_Culture: Wikipedia page on the Culture.
http://en.wikipedia.org/wiki/Culture_series: Wikipedia page on the Culture series of novels.
http://en.wikipedia.org/wiki/Mind_(The_Culture): Wikipedia page on Culture Minds.
http://en.wikipedia.org/wiki/List_of_ships_(The_Culture): Wikipedia list of Culture Ship Names.
An essay on the Culture universe was written by Iain Banks back in 1994. I have reproduced this essay in its entirety here.
This page gives an explanation of the colours used by drones to convey emotions.
An elegant script version of the Marain language glyphs by Daniel Solis can be found here. Note that Daniel does not provide script versions of all of the glyphs identified by Iain Banks and that they do not map to the phonetic sounds that Banks defines either.
A useful guide to Iain M. Banks writing and characterization can be found at Gizmodo.
Also, this Reddit comment lists a considerable number of interviews with Iain M. Banks, which gives at least some insight into the great man's personality, passions and politics
TVTropes has an interesting write-up on culture ideas and themes.
Evidence suggests that Iain M. Banks made use of this Dictionary of Unusual Words as the source for some of his names.