Hey, my question is if you go there on the 90 day visa and you are able to find work inside Japan can you switch it or wait for it to expire and than get a working visa? or would you have to arange with your company to go back to your country (Canada)and get a working visa than go back to Japan... help would be much appriciated

Don't wait for it to expire.. that would result in arrest and deportation.
You could try to change from entry permit to work visa while you are here... it is possible...
But also possible that you would have to go home first.
Check out the rest of the visa and employment threads.

ok thank you for the reply

First off, Japan usually doesn't issue visas for as short as 90 days. Six months is the general minimum.

Secondly, it's now legal to obtain or change a visa from within Japan.

If you are able to and chose to come to Japan without a visa, and can't find a job in 90 days, you can either extend the 90 days for an additional 90, or fly Cebupacifc really cheap to another E. Asian nation. Then return for another 90 days. Like the extension, this can generally be done only once per calendar year.