For example, how would I look up what Sweeden or China's IP range is?
3:50 am on Apr 27, 2006 (gmt 0)
How can I find out what any specific country's IP range is?
4:05 am on Apr 27, 2006 (gmt 0)
IP address ranges are not assigned by country. They are assigned to companies, governments, and organizations that request them -- in many cases, without regard to location. So, a given country may have thousands of ranges assigned to registrants within its bounds. And a given large range (net) may contain smaller ranges (subnets) assigned to registrants in dozens of countries.
You could try a search on "ip to country" if you want to dig deeper.