I'm not seeing anything mentioned in the official blog: http://googleblog.blogspot.com/
But, that doesn't mean anything. I don't recalling normally seeing announcements to search engine changes that have a long lead time before the changes actually happen. Usually, there's a blurb about the changes right before they are rolled out or at the very beginning of the roll out.
The change wasn't actually a setback for sites using legitimate SEO techniques, though it did hurt sites using black-hat SEO techniques (such as spamdexing and link bombing). It was meant to level the playing field, which it did.