So the question has been posed, "what is the law". I offered my definition as the "revealed will of God that binds creature (creation) to obey". I like my definition. That same day I read the first chapter of Thomas Schreiner's book, The Law and it's Fulfillment. The chapter, "The Meaning of the Term Law in Paul" was completely unhelpful. He basically says that the term is used in several different ways (see second post on this topic). He does acknowledge that when Paul uses the term 'law', he is usually referring to the Mosaic Law.
That brings us to another discussion particularly about the Mosaic Law. Theologians, both Dispensationalists and Covenant theologians, have long divided the Mosaic Law into three parts - the civil, the ceremonial and the moral. Calvin and Luther agreed on this, and both agreed that the civil and ceremonial have passed (the civil because it dealt exclusively with the theocracy of Israel and the ceremonial because Christ fulfilled all the 'types' it contained). However, Calvin and Luther disagreed about the role of the moral law in the Christians life. Calvin believed the Christian was still bound to obey the moral law as revealed in the Ten Commandments. Luther, on the other hand, thought the Christian was set free from any obligation to the moral law and that Christian/New Testament ethics was all about the Spirit (though I do not believe he really was, it's obvious why Luther could so easily be charged as being antinomian).
Recently, a group calling themselves "New Covenant Theologians" have pushed against this and asserted that there is no simple neat division of the law that came be made. The Mosaic Law, according the the NCT, is an indivisible whole that has passed away in it's entirety. Admittedly, I do not know much about NCT and have found it difficult to get good scholarly info (try a search on CBD and see what you can find!).
Another group that has risen in Reformed circles is the Theonomists (also called Christian Reconstructionism). They agree with Calvin and Luther that the ceremonial law has passed away because it was meant, in all its symbolism, to point to Christ. They agree with Calvin, not Luther, in that they affirm the normative role of the moral law for believer. Furthermore, they disagree with Calvin and Luther on the role of the civil law. They believe that the civil law as recorded in the Sinaitic Covenant should be the standard by with laws of nations should be judged and to which they should conform. As a natural conclusion, many Theonomists are postmillennial in their eschatology, believing that the church will, by influence (not coercion) Christianize the world and it's systems through evangelism and the that Kingdom will precede the return of Christ. Greg Bahnsen has been the most significant theonomist within the Reformed circle (for a collection of his articles, check here. This one on Theonomy looks interesting, but I haven't read any of it yet), and his influence has only been rivaled by R.J.Rushdoony (who's unique views put him outside the Reformed community).
That's my overview, I'll try to add some comment and evaluation later tonight.