Do you have 2 or more PC's on your desk that each have their own keyboard and mouse? Do you want to control it all from one keyboard and mouse without using a KVM and have the mouse float from one monitor to the next and allow copy and paste between them? Then Mouse without Borders is for you:
I've been using it for a few days now to link my two desktops together and it's working very well. The only hiccough is that I need to sign in to my primary computer first and then the secondary computer second (with its keyboard) if I want them to work together. After that it's all controlled from the primary keyboard and mouse. If I sign in in the other order then I have to use their own keyboards and mice to control them.