F-1 --> H-1B visa = Non-resident of Canada ?

Here's my situation:

I am a Canadian, and lived in Canada until August 2007, when I moved to the U.S. to study on an F-1 Visa.
I've spent 97% of my time physically in the US since that time.
I was on F-1 until June 2009, when I started OPT (Though I think that still is considered being on an F-1.)
In June 2010, I transitioned to OPT-cap-gap (which is still considered F-1 visa status, I think.)
On October 1st, 2010, I will transition to H-1B status.

Questions:

1) I assume that I should probably become a non-resident of Canada as early as possible, to avoid paying Canadian taxes on top of US taxes?

2) I think I can't be considered a US resident (and Canadian non-resident) until I transition off of the F-1 visa and on to the H-1B visa?

3) Can I declare myself a US resident / Canadian non-resident on October 1st -- as soon as I am in H-1B status? (I think I read that the substantial presence test says that I need to be present in the U.S. for at least 183 days... but that any time in F visa status doesn't count.)

You can now become US tax resident since your days of presence now count towrds meeting US tax residency.

You will file a departure return in canad this year, with departure date of Oct 01.

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