First of all, there is no army. There are several thousand guys that want for there to be an army. Of these, a small percentage are former members of the former FAd'H (Haitian Armed Forces). The rest are new, young and largely unemployed recruits.
This unofficial paramilitary force has taken over a dozen or so former army bases around the country. They have a couple of new vehicles, they have guns, they have uniforms (traditional camouflage fare and, for the higher-ups, nylon Get Money jackets featuring Benjamin Franklin), and they are in "training."
While Martelly was campaigning for president, he talked about (and later came up with a $95 million plan for) restoring the army. Originally part of Duvalier's brutal security apparatus, FAd'H has a less-than stellar human rights record and when disbanded by President Aristide in 1995, was replaced by the Haitian National Police (PNH). International donors haven't been thrilled about the idea of funding the reinstatement of the Haitian army (given its history and the resources being pumped into beefing up the police force) and Martelly has had to retreat from this idea, at least publicly, while a government commission debates its feasibility.
Here's where it gets murky: No one knows exactly who is providing the would-be troops with those new vehicles, guns and Get Money jackets. Some think Martelly is doing some behind-the-scenes maneuvering, others believe that anti-Martelly factions within the government are, at worst, looking to instigate a coup d'etat, or, at best, make Martelly look bad. I've heard that they're being funded by Duvalier, who is raising the money from among Haiti's largest and wealthiest families, and also by a well-known drug runner who wants to see UN troops outed in favor of more corruptible local troops. Another theory is that the US government is behind it all. According to a friend, "On the one hand, the ambassador says Haiti doesn't need an army that the US is providing support to the police. Secretly, military and political high-ups are creating plans at the embassy to strengthen the army. They've already given Martelly guns for the army."
The Haitian government has demanded that the paramilitary forces disband, and voluntarily turn over their weapons. Instead, one of the paramilitary groups stormed the national palace while Martelly was in the US for surgery. Though the government has offered back pay and pensions to the former FAd'H members, most have refused, saying instead that they're willing to fight to get their jobs back.
Meanwhile, they have given the government Friday, May 18 - Haitian Flag Day - as an ultimatum: Reinstate the army... or else. Speculation as to what, if anything, will occur that day is as varied as the theories behind who may be backing them. Certainly, though, these guys talk big. They've repeatedly told journalists that that they are willing to fight to the death over this issue.
CBC Dispatches: Haiti's Rogue Paramilitaries (Start listening around minute 18:00 for Susana Ferreira's great radio piece)
Haiti's Former Soldiers Demand Reinstatement of the Army