A few days ago, Hero, the Sharpei almost lost his life to bloat. Luckily, his family recognized the signs and rushed him to the hospital where he had emergency surgery. He seems to be recovering, but is still a bit fragile.
Bloat is a horrible, life threatening condition and quick action is required. The symptoms of bloat are restlessness, pacing, salivation, retching, unproductive attempts to vomit, enlarged and painful abdomen. If you even suspect bloat, get your dog to the emergency room. Better safe than sorry (yeah, Mango has been to the ER for suspected bloat which turned out just to be gas and after some mighty farting he felt better, but I don't regret taking a conservative approach).
Visit his post here to wish him well.
P.S. Try to limit the risk of bloat by not letting your dogs engage in vigorous activity for at least an hour before and after eating. Large chested breeds are more prone to bloat (like both my boys). But be aware that even if you do everything right, it can still happen.