I've been reading up on this on Webmaster Tools but just wanted to see if anyone could explain it a bit better.

I have a website which is going live soon which is going to be set up to redirect to a localised URL based on the IP address i.e. NZ IP ranges will go to .co.nz, Aus IP addresses would go to .com.au and then USA or other non-specified IP addresses will go to the .com address.

There is a single CMS installation for the website.

Does this impact the way in which Google is able to search the site? Will all domains be crawled or just one?

Any help would be great - thanks!