Oscar’s Multi-Monitor taskBar and Synergy are two monitor tools I’ve been needing for quite a while.
The first is a very useful multimonitor helper, that provides an additional taskbar for the second monitor in addition to providing a quick ‘send this window to the other monitor’ key shortcut and title bar buttons.
The second piece of software is kinda like a virtual kvm, whereby you can sit two pc’s and their monitors together and then only using one set of keyboard/mouse on the server pc, access and control the other one. Better still this one works on Windows, Linux and provides limited OS X support.