The announcement on Blogger Buzz.
Blogger's Product Manager, Rick Klau, makes a post on his personal blog.
Pete Hopkins, programmer at Google, shares how the sausage was made when they came up with the plan to migrate FTP publishers to .blogspot or the custom domain feature.
The Blogger team has set up a dedicated blog to communicate with FTP publishers.
Like I said, I don't believe this will affect any garden blogs, but it is interesting--to me at least-- to see Blogger trying to make this as painless as possible for their users.