I want to create a virtual printer driver for Windows. How and where can I start properly? The WDK has some printing drivers examples that do not seems a good introductory.
You can look to the 'minidriver' development in the from Microsoft (Microsoft MDT), that might help depending on your exact needs. If the port you need to deal with (ie: you are going to take the data from an existing printer driver and want to process) you could look to the source code for RedMon. It doesn't support Vista/Win7 but might point you in the right direction.