Here are two examples:
In Ontario, Harris has the Liberals and Tories tied at 31% with the NDP at 20% and the Greens at 17%. Nanos meanshile has the two main parties hovering around 36% (one up a point, one down) The NDP at 22%, and the Greens at 7%
In Quebec, Harris says the Bloc has 37, the Tories 22, the Liberals 17, the NDP 13, and the Greens 8. Nanos has the Bloc at 41, the Liberals at 28, the Tories at 16, the NDP at 10, and the Greens at 6
Nanos reports to adjust numbers based on the census data. This can be a good thing or a bad thing. For example, it's known that younger people generally vote less often, adjusting them 'out' might make your poll more accurate, on the flip side if your 'adjustment' is a little off, so will your poll.
For this coming week we will be averaging Nanos, Harris, and Ekos polls to attempt to get a more clear picture.