Yep so to become a psychologist you need to do a 3 year course (like part of an arts degree) (or more usually a 4 year psch degree which includes 1 year honours (research)). Then you pretty much just need to do one year out and about to be registered and you can do almost anything. But to be more fully qualified in say clinical psych you'd want to do a few years (3) in a master degree etc maybe more if you want to be super qualified.
Psychiatry is your med degree (4-6 years) and then 1 year internship and then I think it's 5 years specialising (although it's a relatively easy specialty to get into as not a huge demand).
Psychiatry is probably more medical and really hard core psych-stuffed up cases, whereas psychology you'll see more family, personal counselling, IQ tests, just general counselling, department of families (you can do almost anything).
I find both really interesting, but don't think I'd want to be one as a career and it's definetly not the reason I wanted to do medicine so I'll leave it to others.
Keen