I just called the Internaltional Tax Services Office to check for the
tax purposes. I have the following reply from the office.

1. If you have short term landing for less than 6 month and you did
not have residential ties with Canada (like your spouse is stayed at Canada,
having a house, a car, etc)
and has no income at Canada (bank account's ineterest does not
count), you does not need to do anything untill you really move to
Canada.

2. When you move to Canada for a long term stayed, you could fill up
the form NR74 to the ITSO for the tax purposes, but it is not
mandatory.

3. You are advice to go through the information at
http://www.ccra-adrc.gc.ca/tax/nonresidents/individuals/newcomer-e.html

IT221 at
http://www.ccra-adrc.gc.ca/E/pub/tp/it221r3-consolid/README.html

T4055 at
http://www.ccra-adrc.gc.ca/E/pub/tg/t4055/README.html

In summary, you does not need to do anything untill you really move to
canada. No tax will be paid.