Whilst this is very good news, on my limited sampling it's not something I'd be sucking into the Wikipedia using a conversion script.
What was the process for adding the A's? Were the A's all complete, without typos?
The "A" articles were compiled and edited by hand by the folks at Project Gutenberg. Many of them were then added to Wikipedia more or less automatically, after which many of them were further hand-edited where appropriate (for example, I updated "Almond" to reflect more recent biological classification).
The same process will be needed for these, so that should keep me and others busy for a long time. I'm also curious whether they plan to scan the illustrations. Those, too, are now in the public domain, and some of the articles make little sense without them (look at "Abbey", for example).