Zvika Krieger at TNR has a solid report on the demise and dissolution of the Minuteman movement:

In this environment, Gilchrist's movement is falling apart, overtaken by new members whom he describes as "troublemakers with personality disorders and criminal propensities." In contrast, he insists that the group's original members were able to give voice to the immigration concerns of ordinary Americans because they demonstrated "a passionate allegiance to the United States of America and its priceless principles." There is no doubt that the Minutemen--aided by sympathizers in the media like Lou Dobbs--drove the national conversation in 2005. But whether the enormous wellspring of American anger over illegal immigration that they claim to have tapped into actually existed is another question.

However, it's not merely Gilchrist's organization (The Minuteman Project) that's falling apart; so is the other major "Minuteman" outfit, cofounder Chris Simcox's Minuteman Civil Defense Corps.

For what it's worth, I reported on this aspect of the story, as well as Gilchrist's, back in October for The American Prospect:

Today the Minuteman movement is beyond mere disarray; it is in the early stages of complete decay. The arc of the Minutemen's decline and fall happens to trace almost precisely that of previous right-wing populist movements, notably the Klan of the 1920s and the militias of the 1990s. The pattern goes like this: The group is beset by financial manipulators who seem naturally drawn to them. Then, following an initial wave of popularity, the group splinters under the pressure of competing egos into smaller, more virulent entities who then unleash acts of public ugliness and violence that eventually relegate them to the fringes.

The Minutemen haven't quite reached that final stage yet, but they are well on their way. And while that may be welcome news to those who oppose the Minutemen's nativist agenda, that last stage represents some natural and equally toxic consequences.