Yes, American Samoa will be competing in the 2012 London Olympics.
There will be a total of 205 countries are competing in the London 2012 Olympics.1000
Yes. Vietnam is competing at the 2012 Summer Olympics in London and has 18 athletes competing in 11 sports
Wikipedia lists Germany as having 391 athletes competing in the 2012 Summer Olympics in London
Over 10,000 athletes from 204 countries will be competing in the 302 events for the 2012 London Summer Olympics