I was really suprised that Ghana beat the Czechs in such a fashion. What suprised me a bit more is that the US held Italy (of course Italy had to score the US goal for them it seems...). No mind. Say the US gets second in their group (and that's not a given by far). They draw the Brazilians. Game over. The game I'll be watching (and it's still a possiblity I believe) is 1A vs. 2B. Then we'll see if the Germans still 'love' the English as the papers have been saying after that..
I wouldn't complete count out USA against Brazil if they should meet. Brazil has not looked very impressive so far -- if the US can find someone to actually finish a chance or two, they can score. The real challenge will be preventing the Brazilian counter-attack. On the whole, I think the same style and strategy used against Italy would serve Team USA well against Brazil -- high-tempo, agressive, break up the rhythm.
If the US makes the knockout round, they will have overachieved, given the group they were in. At least it keeps some sense of momemtum going for US Soccer, a repeat of 1998 would have been disastrous.