Hammered Out Bits continues to provide good iron smelting data at a tremendous rate.
Lee Sauder and Skip Williams have a good page of iron smelting links at The Rockridge Bloomery. (Mel Brooks movie quotations aside)
The Early Mines Research Group has an ongoing smelting effort as well, check out the "experimental archeaology" and members-projects links.
It looks like a lot of different people are (or recently have been) interested in early metal smelting re-creation, and I would love it if whoever catches the bug next had an easier time finding resources than I did, so please: send me your references.