There are two recent articles of note on the Megiddo find.
On the one hand, there is an article over on Sightings, a publication of the Martin Marty Center (University of Chicago). Laurie Brink (Assistant Professor of Biblical Studies at Catholic Theological Union) provides an overview of the situation regarding dating and reaffirms the sort of cautions on theories of an early date that I have expressed here on my blog before (she speaks of the “archaeological penchant for early dating”). She also notes Megiddo’s “competitor” for the earliest church, namely the house-church (domus ecclesiae) at Dura Europa which is dated to 240-41 CE. The Dura Europa find represents a building that was originally a house that was transformed for use as a church, what we call a house-church (on potential house-synagogues, see my earlier post here). Brink also mentions recent redatings of archeological finds that push dates later, such as Magness’ redating of the Sardis synagogue (on which see my post here). Overall, Brink tends to the view that the Megiddo find is more likely dated to the time after Constantine’s Edict of Milan in 313 CE. (There are some spelling errors in the article [e.g. Edit], so beware). Brink concludes: “Thus the significance of the Megiddo discovery may lie neither in its date nor its uniqueness, but in its context, where it may prove to be a rare archaeological example of an ordinary center for early Christian worship. As such, it would not compete against the Dura Europos church, but rather find commonality with it.”
The other article is at Haaretz.com and gives you somewhat of a prisoner’s perspective on the find: ‘ “First I found corner,” Batir continues. “I go, dig with hoe, saw here a little, 10 centimeters, and I think to myself there is something here. There was plaster, shards, no pictures. After that I saw fish and I know it is Christian.” ‘