No, the American Flag Bearer for the opening ceremony has not been announced yet. Up to now there's been a total of almost 80 flag bearers announced, some countries like to keep things a surprise until the actual ceremony while others still have yet to decide.
For a detailed list of each country's flag bearers you can always try http://www.wikipedia.org/ or if you prefer a more succinct sports sites recap you can read the Infinite Monkeys:
http://infinit8monkeys.com/london-2012-o...
There is also an interesting Breakdown of the Flag Bearers per sport. So far I am not surprised to see that Athletics is leading the field (there are just so many disciplines that fall under that category)
http://infinit8monkeys.com/2012-summer-o...
Personally, as far as the United States go, I would think that Phelps is the clear cut favorite to carry the flag, but you never know ;)
It has not been decided. People assume that it will be Phelps, but America barely ever goes with the conventional choice. Typically, it is an athlete that has a heart-gripping story behind them or a long road to get to the olympics. Still, if I would guess, I would say Phelps or Kobe Bryant.
Tom Cruise
Justin Gatlin, flanked by his lawyer and his pharmacist.
Do we know who will carry the American Olympic flag yet? Michael Phelps I guess...
