Not exactly new – but I am loving ShareMouse – an almost ridiculously easy to use virtual keyboard and mouse sharing app. To clarify that, it works a bit like a KVM. You plug a keyboard and mouse into one machine on your network – and can use them with any other Windows or Mac computer on your LAN that has ShareMouse installed.
I struggled with the open source Synergy for a while and found it a bit on the glitchy/IMPOSSIBLE TO CONFIGURE side (especially in a mixed 64/32 bit Mac/Windows environment, which is where I live).
ShareMouse, launched at the end of August, is install-and-use-tastic. I put it on on a Hackintosh and a Win 7 PC. The “monitor manager” window lets you virtually position your screens. To switch between them you just keep going when you hit the edge of your monitor – just like any shared set-up. And, you can drag and drop files between screens too.
Currently in beta so, therefore, currently free.