That depends on what type of IP address you are talking about. If you share the cable Internet using a router, you have two IP address (private and global). Private being the IP address handed to you from your DHCP server on your home router; global meaning the address that every one on the Internet sees and is handed to you from your internet service provider (ISP). You can change the private (internal) IP address simply by disabling DHCP and manually setting up the IP information on the TCP/IP properties; changing the global(external) requires you to contact your ISP or wait until your DHCP lease expires.