A few years back, I wrote about Synergy, an application that allows you to use one mouse to control the cursor across multiple desktops. It’s like having the efficiency of multiple monitors combined with the power of multiple mice. Microsoft released a Garage Project, their little incubator for their engineers’ off the clock projects, called Mouse Without Borders that does much of the same thing. While Synergy is cool because it is multi-platform, Mouse Without Borders is for Windows only but it allows copy-pasting across desktops as well for both text and files.
You can get the application at http://aka.ms/mousewithoutborders