As far as I can tell Google Editions has already been launched. All we're waiting for right now is for Google to open the ebookstore and start selling.
If you've been following Google Editions in the news, then you know that it will be Google's ebookstore. It's an expansion on Google's digitization efforts (the much maligned Google Books).
One detail that I haven't seen in the news is that Google have been signing rights holders for quite some time now. Mike Cane tipped me to this PDF a couple weeks ago. (It's a welcome letter for GE.) I was little surprised because most every article I'd read on GE discussed the future launch and the PDF assumes GE is currently running.
I followed the suggestion of the welcome letter and I created a Google Books Partner account. Sure enough, there was a tab for Google Editions. I've read it a couple times now, and it appears to have all the parts of a contract that you'd expect between an author and publisher (or distributor, ebookstore, etc). And that tab has been there for at least 3 or 4 weeks now.
There's actually more than just the tab. The FAQ for GE is already available. I can't tell when it was posted, but it seems pretty complete to me.
I don't know when GE will be opened, but I do know that Google have certainly laid the groundwork.