i will try to answer all of your questions. I apologize in adavne for my spelling, i am on a different computer with tiny keys:
psyds last between 5-7 years. in general it is 4 years of course work, with one year of internship, followed by graduation. there was an article in the APA student journal the other month that had an "under a decade club", referring to time to completion of a doctorate.
also important: in america you cannot call yourself a psychologist without a doctorate, except if you have a masters in school psychology.
1) internship is a requirement for the degree. you cannot complete a phd or psyd without the internship. as such, state laws have internship requirements. so i guess the answer is that you would have to do an internship to create an equivalent degree and meet state licensure law requirements.
2) for a general post doc: it is after graduation but before licensure. in the states, once you graduate you do not have a license to practice independently. state laws require one year of supervision of supervision after graduation from the program. these laws typically also have internship hours requirements as well. moreover, we have a third party payor system here (i.e., insurance pays for the services, not the individual). most insurance panels will not let you into their system until you have been licensed for 3-5 years after you obtain a license. so having a post doc as a means to obtaining patients is pretty important.
3) yes, all americans have to complete the internship and standardized exam. the one exception is that california has a different standardized exam than the others.
4) yes, internship pay is highway robbery. then again, they cannot bill for your services.
5) internsip is HIGHLY competitive. the worst sites have a minimum of say, 20:1 applicants to acceptance. at the best sites you are talking about somethign like 500 applicants for 1-2 positions.
6) internship is a formalized process. the process basically works thus: you complete all coursework, you get several letters of rec, you complete a 30 page application, you prepare your cv, you then pay a company somethign like $90 to join their service, you search a database and find internships you want to apply to, you send your matierals to them along with any special things they want (cd roms, etc), you are then notified of who wants to interview you, they call and schdule the interviews at their faciliy at their convenience, you then fly out to whereever they are, interview, after several interviews you tell the service how you rank the internships in terms of preference, they secretly do the same, a computer system matches you or not. you are then notified if you matched. a weekend later you are told where. if you do not match you have to wait a year and do it all over again. they determne who they employ based upon the letters of rec, how many hours of client contact you have had (phds average around 2000hrs, with psyds supposedly lower although mine was higher than the ph average)., what kind of patients you have seen (this can get VERY specific including as they require you to describe the deongraphics of everyone you have ever seen on race, ethicnicity, sexual preference, SES, learning diasbaility, etc. ), how many tests of what variety you have given, etc.
i understand your interest in working in another country. a while back i looked at a job in the NHS. however, our systems are incredibly different. being aware of some key differences is a great idea.