The way I read this is that everyone not in the government is the militia... as for well-regulated:
1714: "The practice of all well-regulated courts of justice in the world."
1812: "The equation of time ... is the adjustment of the difference of time as shown by a well-regulated clock and a true sun dial."
1848: "A remissness for which I am sure every well-regulated person will blame the Mayor."
1862: "It appeared to her well-regulated mind, like a clandestine proceeding."
1894: "The newspaper, a never wanting adjunct to every well-regulated American embryo city."
The phrase "well-regulated" was in common use long before 1789, and remained so for a century thereafter. It referred to the property of something being in proper working order. Something that was well-regulated was calibrated correctly, functioning as expected. Establishing government oversight of the people's arms was not only not the intent in using the phrase in the 2nd amendment, it was precisely to render the government powerless to do so that the founders wrote it.
http://www.constitution.org/cons/wellregu.htm
What the Framers said about our Second Amendment
Rights to Keep and Bear Arms
http://econfaculty.gmu.edu/wew/quotes/arms.html
"The best we can hope for concerning the people at large is that they be properly armed."
-- Alexander Hamilton, The Federalist Papers at 184-188
If the representatives of the people betray their constituents, there is then no recourse left but in the exertion of that original right of self-defense which is paramount to all positive forms of government, and which against the usurpations of the national rulers may be exerted with infinitely better prospect of success than against those of the rulers of an individual State. In a single State, if the persons entrusted with supreme power become usurpers, the different parcels, subdivisions, or districts of which it consists, having no distinct government in each, can take no regular measures for defense. The citizens must rush tumultuously to arms, without concert, without system, without resource; except in their courage and despair.
-- Alexander Hamilton, Federalist No. 28
"That the said Constitution shall never be construed to authorize Congress to infringe the just liberty of the press or the rights of conscience; or to prevent the people of the United States who are peaceable citizens from keeping their own arms ... "
-- Samuel Adams, Debates and Proceedings in the Convention of the Commonwealth of Massachusetts, at 86-87 (Pierce & Hale, eds., Boston, 1850)
"[The Constitution preserves] the advantage of being armed which Americans possess over the people of almost every other nation...(where) the governments are afraid to trust the people with arms."
--James Madison, The Federalist Papers, No. 46
"To suppose arms in the hands of citizens, to be used at individual discretion, except in private self-defense, or by partial orders of towns, countries or districts of a state, is to demolish every constitution, and lay the laws prostrate, so that liberty can be enjoyed by no man; it is a dissolution of the government. The fundamental law of the militia is, that it be created, directed and commanded by the laws, and ever for the support of the laws."
--John Adams, A Defense of the Constitutions of the United States 475 (1787-1788)
"Before a standing army can rule, the people must be disarmed; as they are in almost every kingdom in Europe. The supreme power in America cannot enforce unjust laws by the sword; because the whole body of the people are armed, and constitute a force superior to any band of regular troops that can be, on any pretense, raised in the United States. A military force, at the command of Congress, can execute no laws, but such as the people perceive to be just and constitutional; for they will possess the power, and jealousy will instantly inspire the inclination, to resist the execution of a law which appears to them unjust and oppressive."
--Noah Webster, An Examination of the Leading Principles of the Federal Constitution (Philadelphia 1787).
"Who are the militia? Are they not ourselves? Is it feared, then, that we shall turn our arms each man against his own bosom. Congress have no power to disarm the militia. Their swords, and every other terrible implement of the soldier, are the birthright of an American...[T]he unlimited power of the sword is not in the hands of either the federal or state governments, but, where I trust in God it will ever remain, in the hands of the people."
--Tenche Coxe, The Pennsylvania Gazette, Feb. 20, 1788.
"Whereas, to preserve liberty, it is essential that the whole body of the people always possess arms, and be taught alike, especially when young, how to use them; nor does it follow from this, that all promiscuously must go into actual service on every occasion. The mind that aims at a select militia, must be influenced by a truly anti-republican principle; and when we see many men disposed to practice upon it, whenever they can prevail, no wonder true republicans are for carefully guarding against it."
--Richard Henry Lee, The Pennsylvania Gazette, Feb. 20, 1788.
"What country can preserve its liberties if its rulers are not warned from time to time that their people preserve the spirit of resistance? Let them take arms."
-- Thomas Jefferson to William Stephens Smith, 1787. ME 6:373, Papers 12:356
"No Free man shall ever be debarred the use of arms."
-- Thomas Jefferson, Proposal Virginia Constitution, 1 T. Jefferson Papers, 334,[C.J. Boyd, Ed., 1950]
"The right of the people to keep and bear ... arms shall not be infringed. A well regulated militia, composed of the body of the people, trained to arms, is the best and most natural defense of a free country ..."
-- James Madison, I Annals of Congress 434, June 8, 1789