You do show sooner with the 2nd. I'm 8 weeks now with my third and even though I've lost weight with my morning sickness (10 pounds to be exact), my belly is getting bigger and my pants seem to be shrinking. But I'm sure it's just the washer and dryer Haha.
I'm only on my first, but I swear, even though I wasn't really gaining any weight (only about 5 lbs for the first half of pregnancy) I couldn't fit into my regular jeans pretty much right away. I guess it was the spreading hips that did it!