I need some advice on law education in general. I am a canadian citizen altough I have completed an LLB (Bachelor of Law) in the UK and was wondering if I could still practice in Canada, or even USA, Australia?

You need to take the NCA exams to practice in Canada - this is a terribly protectionist process. Once you have completed the NCA challenged exams (anything from 3 to 12), you can then do the bar exam.

As for the US, check out the requirements for each state - it varies.

It's all available on the internet.