My previous TPM post notwithstanding, subsequent developments tend to point away from an Iraqi Anthrax connection. First, it seems there is a growing pool of admittedly quite circumstantial evidence pointing in the direction of domestic terrorism. Either a purely domestic operation a la Tim McVeigh, or one in sympathy with bin Laden et.al., operating without close coordination with people overseas.
One of the most interesting pieces of evidence can be found in this article by Scott Ritter, a former weapons inspector, permanent hot-head, but never someone who you'd expect to be exculpating Saddam if the facts didn't unmistakably point in that direction. He makes three points: 1) that the weapons inspectors did a pretty good job destroying the Iraqi bioweapons operations, 2) that it simply wouldn't make sense for Saddam to involve himself in something like this since he's already making progress on his major goal, lifting sanctions, and 3) that the strain of Anthrax that the Iraqis worked with isn't the same as that found in Florida, DC and New York. (The not-unreasonable counter-argument from the Iraq hawks would be that the Iraqis have now had three years of unmonitored time to hatch new plans and perhaps new microbes.)
Taken together, Ritter makes a pretty strong case that there's at least no good evidence for an Iraqi connection to date.