Unless you have close family members living in the USA (or you marry a US citizen) you've absolutely no chance of moving to the USA. Even if you've got immediate family living in the USA, the process is extremely lengthy. (Friends of mine moved to the USA when they retired, to join their son who is married to an American. It took them nearly three years to get through all of the formalities).
Getting a visa to work in America (even for a short term, without actually moving there permanently) is extremely hard Apart from a few special exceptions (such as Camp America, businessman visiting for short-term periods, journalists and academics) the usual test is that visa applicants must have 'extraordinary ability' within certain fields. (e.g. David Beckham can work in the USA because he's an international player. A Premier League player, without international experience, would probably not qualify. Similarly talented research scientists, working on a possible cure for cancer, can get visas to work in the USA; someone who just has a science degree can't).
For information upon getting a visa to work in the USA, without being granted residence status, see here:
http://www.usembassy.org.uk/cons_new/visa/niv/index.html
Similar (but stricter) criteria apply to emigrating to the USA:
http://www.usembassy.org.uk/cons_new/visa/iv/index.html
Unemployment in the USA is high. The Obama administration has banned any organisation which has received state funding, to help it through the recession, from offering new employment to foreign nationals. Further, it has pledged to rigorously enforce the rules to keep the number of new immigrant workers elsewhe