The other day I referred to Hendrickson's sample chapters available on-line. Thanks to Holger Szesnat for pointing out something similar at Oxford University Press, though at present much less extensive than the Hendrickson's one:
OUP Reading Room: Biblical Studies
There are several things of interest here, including several selections (in one PDF file) from the Oxford Bible Commentary ed. by John Barton and John Muddiman and the opening chapter of E. P. Sanders's Paul: A Very Short Introduction.