The University of Pennsylvania has made available online a series of PDFs containing the New English Translation of the Septuagint (Oxford, 2009). In keeping with the NETS’s printed text, the beginning of each file also contains a good introduction to the translation that it provides (HT: Charles Jones).
It should be noted that one cannot copy or print out these files, according to the website. I have not tried it, but one should be able to copy and paste from the files, since the files are searchable. Usually searchable PDFs can be copied from the view screen and then pasted into your own document…