Well one must wait for an official offer from Google first, then a couple weeks later Apple will up it, then having anticipated this as any market genius would have, Google will come back with a higher offer within a week.
From my experience the price will usually jump to just a buck or so under the offered price. Then the volatility and volume will practically vanish. There it will sit until further news.
Google would be smart to hold their first offer a little low, knowing full well a competitor will bump their bid for the reason I initially laid out. I look for the initial bid around 4.5B. Apple will then up it to 5.2 Google then offers 5.9 and the deal goes down.