It's apparently happening today. Details coming in over at MLB Trade Rumors. Eight years (including 2008, because there's a bonus to be paid immediately) totalling something like $47M, with fancy-schmancy escalator clauses and other NFL-sounding things. Upshot: two years of free agency bought out for the Brewers, riches secured for Braun, and everyone can now commence having the same conversation about risk vs. reward that we had when Longoria and Peavy and all of the others signed their deals.
Meanwhile, Prince Fielder is busy painting a "Will Mash For Food" sign.