Your gadget may exist in one of two locations, depending on the nature of
the gadget, Global, or Local. Go to Start/.../Run, and type:
%userprofile%\appdata\local\microsoft\windows sidebar\gadgets
If it is Local, you can zip the entire folder (*.gadget) and send it to your
friend, who can extract the folder to the same location. (Doubleclicking a
zip file offers this option)
They then simply click the '+" at the top of the sidebar, and doubleclick
the gadget icon.
A Global gadget requires a bit more geek power. You need to remove Your
permissions and ownership rights when you copy the files to the zip. You
find global gadgets at:
C:\Program Files\Windows Sidebar\Gadgets
(these should be installed to the local gadget area by your friend)
I like to use RoboCopy for the work, since it has switches for that but
there are several ways available. Copy *.Gadgets to a local folder, remove
the ACL's and zip.
>> Stay informed about: How to copy a sidebar gadget