You'll need to work at this and the resources of a really good library (University standard).
You could start by reading Plato's dialogue Gorgias.
I suggest you following up the information available from the IEP entry. The most recent entry there is McComiskey, Bruce. Gorgias and the New Sophistic Rhetoric. Carbondale: Southern Illinois, 2002 and I would start by looking at that.
Another citation in the same entry is Gorgias. Encomium of Helen. Trans. Douglas MacDowell. Glasgow: Bristol Classics, 1982. I don't find any suggestion that this work exists as an independent text in Perseus Digital Library, so I'm not at all sure what that's about. However, Wikipedia entry on Gorgias has Gorgias. "Encomium of Helen" The Norton Anthology of Theory and Criticism. Eds. Vincent B. Leitch, et al. New York: W.W. Norton & Company, 2001. 30–33.
There's another source that's likely to be useful cited in the IEP entry on Sophists - Gibert, J. 2003. 'The Sophists' In C. Shields (ed.), The Blackwell Guide to Ancient Philosophy, 27-50. Oxford, Blackwell.
The Wikipedia entry (unlike the IEP entry) does explain why post-modernists might have found Gorgias attractive:-
Gorgias's rhetoric is frequently elusive and confusing; he makes
many of his most important points using elaborate, but highly
ambiguous, metaphors, similes, and puns. Many of Gorgias's
propositions are also thought to be sarcastic, playful, or
satirical. In his treatise On Rhetoric, Aristotle characterizes
Gorgias's style of oratory as "pervasively ironic" and states that
Gorgias recommended responding to seriousness with jests and to jests
with seriousness. Gorgias frequently blurs the lines between
serious philosophical discourse and satire, which makes it
extremely difficult for scholars to tell when he is being serious and
when he is merely joking. Gorgias frequently contradicts his own
statements and adopts inconsistent perspectives on different
issues.
I don't find in these entries anything that I'm sure would give a post-modern view of Gorgias. There's an listing in IEP for Jarratt, S. 1991. Rereading the Sophists. Carbondale: Southern Illinois Press. The title (and the date) suggests that this might be a post-modern reading.
The SEP entry The Sophists has a slightly different take, but confirms my feeling that you should not expect to find any great philosophical illumination here:
His extant writings include display speeches, purportedly in defence
of Helen and Palamedes against charges of treachery (DK 82B11 and
11a); they seem to be intended partly as examples of stylistic
brilliance for its own sake and partly as demonstration of skill in
adversarial argument, ‘making the weaker argument the stronger’. In
addition, we have a philosophical essay ‘On Non-Being or On Nature’
(DK 82B3), purporting to be a rebuttal of Parmenides, in which he
maintains that nothing exists, that if anything did exist it could not
be known and that if anything could be known it could not be
communicated. Scholarly opinion has been and remains divided as to
whether this was intended as a parody of Eleatic writing or as a
serious piece of philosophy. What can definitely be said is that it
shows some knowledge of Parmenides, that it at least raises serious
philosophical questions, such as the relation of thought to reality
and the possibility of referring to things which do not exist, that no
question which it raises is developed to any significant extent and
that most of its arguments are extremely feeble. It reads like a piece
written by a clever man with no real interest in philosophy, but it is
doubtful whether we shall ever know why he wrote it.
"DK" is abbreviation for:- Diels, H. and Kranz, W. (eds), 1974, Die Fragmente der Vorsokratiker, Berlin, Weidmann, (volume 2), 252–416.
English translations (including additional material):
R.K. Sprague (ed.), 2001 The Older Sophists, 2nd edn., Indianapolis: Hackett;
D.W. Graham (ed.), 2010, The Texts of Early Greek Philosophy, vol. 2, Cambridge: Cambridge University Press.
You could also tap publishers listings for more recent work.
