Hi Frans,
Welcome to the forum. There's a famous show in Canadian TV called Dragon's Den and one of the judges (dragon) on the show, Arlene Dickinson immigrated from South Africa when she was little with her parents. Although this is one of the non-so-typical rag to riches story - just wanted to say that the road ahead for moving can be daunting especially for a family with kids.
To answer your questions,
I have been working as an accountant for almost 20 years, but I have not finished my degree.....will I be able to find a job in Canada?
It is not impossible. It is easier if you did not somebody here or have connections to some companies. If you come without any connections, then your first hurdle getting the hiring guys to even pick up your resume. Hopefully the years of working experience counts. I would say it all depends on who's doing the head hunting.
Are the salaries sufficient to have a normal life? Currently with the cost of living in SA, a normal salary is not enough to sustain our family. My wife home schools our boys, as the struggle in mainstream schools.
That depends on where you live and how much you are getting. Why where you live? Well apart from cost of living see link http://www.numbeo.com/cost-of-living/co … try=Canada, don't forget the provincial income taxes and sales taxes. But don't forget too that if you do get an immigrant status (PR) then you get additional child car benefits (though not fantastic but everything helps). Healthcare is free though. But that doesn't count your cost of drugs - you'll need a medical insurance for that (but most companies gives their employees and their family medical insurance). Also depending on where you choose to settle, the compensation may be lower or higher e.g. Alberta typically pays about 20% higher than say for example places like the maritime provinces. With 3 kids it may be wiser to take care of them at home because the cost of day care can be very high - so watch that carefully.
Should I find a job in Canada before leaving SA, or should I first go to Canada, get a job and then move my family?
Of course that would be ideal but the chances of that happening is slim although not impossible. I know a family from Ireland that moved here after getting a job offer.
The other is probably what most people do. But that requires lots of funds on your side to sustain you for awhile while looking for a job.
Hopefully this helps.