ChangeMAC

ChangeMAC is one of the fastest ways to change the MAC address of any installed network adapter.
There are plenty of similar apps out there on the market, but ChangeMAC tries to set itself apart with what can be very well considered one of the simplest user approaches in this particular software category.
After launch, you get just a tiny GUI that shows you the installed network interfaces and lets you pick the one whose MAC address you wish to change.
A dedicated option just under this drop-down menu requires you to input the new MAC address by simply typing the data in an empty field. Just press “Save” and you are ready to go.
ChangeMAC doesn't provide a “Restore” tool, but it's enough to simply check the “Default” option to get back to the original settings.
There's one important thing that needs to be mentioned though. ChangeMAC works on most Windows versions released so far, but administrator privileges are required on newer iterations. For example, if you're launching it without administrator access on Windows 7, you won't be able to see the installed network interfaces.
On the other hand, ChangeMAC works fast and easy, without any impact on system performance. It makes the MAC address modifications instantly, as soon as you hit the “Save” button.
All things considered, ChangeMAC clearly serves its purpose of becoming a very simple way of changing a MAC address. You're not assaulted with unnecessary features, and while experienced users might miss some more advanced options, rookies are very likely to be pleased with this app.