I'm an Aussie, who works with a few Canadian's as an slp in the US. The easiest thing and the first thing that you should do is find an agency who will initially employ you. They will 'hold your hand' through the whole process, tell you what you need to do, as well as sponsor your visa. My company emailed me a 'to do' list and kept checking in to make sure that I was on target for completing all of my accreditations and licenses. Let me know if you have more questions.
My blog that has info on being a 'traveling' SLP is adventuresinspeechpathology.wordpress.com/