Driving in Canada (Toronto)

Hi:
I am looking to relocated with work to Toronto and I have a tonne of questions, so I may be on here a bit :)

So.....first,

I am going to need to drive, can anyone offer any advice on a couple of questions

- I have a full English driving liscense, can I drive on this?
- how easy is it to switch to a Canadian drivers liscense?
- how difficult will it be to lease a car when I first get there?

Soooooo, many questions and any advice is appreciated.