Log in into your site click "Edit Page"
In Edit mode click "Insert" -> "More Gadgets..." -> "Add gadget by URL"
paste this url
http://hosting.gmodules.com/ig/gadgets/file/108306549906760602918/gadgetforgoogleio.xml
and click "add"
Don't forget to Save your changes
Source: http://code.google.com/p/m-kupriyanov-gadgets/