This year's Commonwealth Games are being held in Dehli, India 3- 14 October.
Here is the official 2010 Commonwealth Games website
For general information, start at the Commonwealth Games Federation site - this is the official website for the Commonwealth Games. You can check which countries are involved by clicking on the countries tab on the top navigation bar. They are listed by continent (or area of the world) so click on each continent to see the individual countries who are part of the commonwealth. There's also a map of where to find each country.
The NZ Olympic Committee website has information about the NZ team.
For general information about the Commonwealth, try the Young Commonwealth pages (primary level) or the Commonwealth Secretariat website (secondary)