(was Canada still a british Commonwealth in 1903?)

still is in 2002 mate, and will be in 2003

Canada was not part of the British Commonwealth in 1903 - nowhere was, because it didn't exist. In fact, it still doesn't. The Commonwealth of Nations replaced the old British Empire, most member states of which were not ever "commonwealths" themselves. NZ was a Dominion, as was Canada. Australia still is a Commonwealth, and many of the names on the list are not even sovereign states of any description. My next-door neighbour, for example, comes from Aitutaki, one of the islands making up The Cook Islands. There is no longer any such "state", for want of a more precise word, as "Malaya," "Southern Nigeria", or "Zanzibar, "and the Commomwealth has been expanded to include many African nations that were never part of the British Empire, including Mozambique. The current Sec-Gen of the Commonwealth of Nations is a former NZ Deputy PM, Don MacKinnon, and, while the Queen is currently the head of the Commonwealth, the chances of that job being dynastic are about as good as my chances of winning a Nobel Prize.

edit:
Here is the current list of members of what is, it seems, officially called simply, "The Commonwealth":
http://www.thecommonwealth.org/dynamic/Country.asp