Media for IP Address Block Assignment

Folks:

Let us assume that a large multinational company is about to setup a standard corporate network with global reach. Here are a few related questions:

HOW does the company get an IP address block assigned to it for its global network to function ? * WHO assigns the IP address block to be used in the company's global network ? * Does the company have a CHOICE in selecting its IP address block ? * Can someone walk me through the PROCESS from the point of applying for a block of IP addresses to the point of having same assigned to the company ?

Any references/links to good literature describing the assignment process would be deeply appreciated.

Thanks, Jo.