1- Windows 8 has it's own Ink API built-in which works with all digitize pen. It provides palm rejection, pressure sensitivity, tracking, eraser functionality and extra button on pen support.
2- They are some software that don't support Windows 8 Ink API yet, such as PhotoShop. They only work with Wacom WinTab drivers and some with Wacom and also N-Trig. For such programs, you need to install, for the Surface Pro 1 and 2, the Wacom WinTab Feel-It drivers
3- You can get the drivers here:
Wacom Feel Driver | Wacom Americas
4- Wacom digitize pen technology requires to be calibrated, as the entire pen is being tracked. We all hold the pen differently, so its essentially required to calibrate the pen for the best accuracy, unless you just happened to hold the pen the same way as the Surface Pro 1/2 were calibrated to by default.