Pwo = post-workout, which is within 10-15 minutes of finishing a workout. This is where your body needs instant simple carbs to spike insulin and go anabolic. Simple sugars of any kind will do, dextrose is optimal because it's the simplest form of sugar available .. failing that, gatorade or powerade powder, fruit juice (I like cranberry with strawberry whey, very yummy), very ripe fruit (not optimal) or even simple table sugar. You also add protein (fast-digesting like whey or egg whites) to this post-workout meal so the rebuilding process can begin immediately - hence the post-workout drink being dextrose and whey powder. As for the ratios I've seen conflicting reports, I aim for 60-100g of simple carbs (quantity not really important) and minimum 60g of protein. When your gains start slowing down, try doubling the whey in your pwo drink and see what happens!
Ppwo = post post-workout, which is about 45 mins to an hour after your post-workout meal. This is where you need a nice balanced meal of protein and complex carbs (steak and rice, chicken and potatoes, tuna and pasta or whichever other combination you'd like) to hit on the second 'window of opportunity' in which the body can optimally utilise protein after a workout (the first being the pwo window) - basically we didn't need science to tell us this, I'm almost always starving about an hour after a workout despite being bloated from the pwo drink.
*Note that I think post-post-workout is a purely british thing, I've asked americans about it and they don't use the term (they still know about the window, just don't call it ppwo) - you'll notice that Diesel's bulking guide correctly advises a pro/carb meal ppwo (MRP and potatoes if I remember rightly).
True example (myself, yesterday):
pwo - 300ml cranberry juice, bottle of green apple gatorade, 75g protein (in whey form). (protein/simple carbs)
ppwo (about an hour after pwo):
three (100g or so) lean pork burgers and a bucketload of basmati rice, with a salad. (protein/complex carbs)
As for why eatprotein first, well, again there's a good deal of science in it, I'll post it later 'cause I'm starving right now.