MCI and SprintLink are partitioned (fwd)

Where can I find mapping information from the in-addr zones to
attributes like service providers, or even simple things like
countries (that uses a consistent data base)?

Check out the RADB or you nearby router's routing tables. These will
get you route/AS mappings, and then the NIC's whois will get you
AS/name mappings.
  --asp@uunet.uu.net (Andrew Partan)