question about registration

I've been looking into emigating to canada (us now off)and understand the basic steps needed to take. I am going to apply for the registration (with BC) and was just wondering if i get approved to take the exam/get a temp license how long will that approval be valid for. so say i got the approval and we decided to hold off looking for a job and starting the visa process for a while to save some more money how much time will i have before i have to re-apply.

That's a question best asked of CRNBC. My guess would be two years, but it's just a guess. The nuances of professional immigration are not my strong suit.

Also is it possible to take the exam before moving out there and working as i though if it is i might think about doing that before applying for jobs and visas

thanks

I'm pretty sure you could write as soon as you've been given authorization. There are other posts somewhere in here that talk about having written and passed and now working on visas and such. A pass is a pass, and as far as I know, there's no expiry date on passing. If there were, a lot of people who took time off to raise families and are now coming back into the workforce would be faced with writing again, and not just a refresher course.