Spoofed ip is a lightweight, easy-use Mac Address scanning and changing software. Don't let its small size fool you! It's filled with features such as:

It's shockingly easy to use ? just a simple input and click, that's it!
It can scan any range of IP for the proper Mac Address.
It supports exporting results of your scan to a text file.
It runs on all Windows? operating systems.
It supports any network cards under Windows Me/95/98/NT/2000/XP/2003.
It supports changing back to its original physical address.
It recommends the proper Ethernet network card.
It displays the information of your computer.
It automatically checks the legality of IP range.
It supports changing Mac searching speed.
what does all this mean to you? Simple...

You don't blow your time calling the ISP vendor and ask them to update the registered Mac Address to match the new hardware. Some Cable Modem ISP's assign IP addresses base on the PC's MAC addresses. For whatever reason, if you need to swap 2 PC's regularly to connect to the cable modem, it would be a lot easier to spoof Mac Addresses rather than to change Network Interface Card (NIC).
You can scan the Mac Address of destination computer.
You can perform security checking on MAC Address based authentication and authorization systems
You can build Stand-by (offline) systems with the EXACT same Computer Name, IP address, & Mac Address as the Primary Systems. If Stand-by systems should be put online, NO arp table refresh is necessary, which eliminates extra downtime.
Test network management tools.
Some software can ONLY be installed and run on the systems with pre-defined MAC address in the license file. Now you can install one of these applications to another system with a different NIC.
Troubleshoot Network problems: ARP Tables, Routing, Switching, etc.