The idea of getting into the Zone really comes from athletics. That combination of physical co-ordination, alertness and mental peace is what you need to perform physical actions well, unhindered by nerves or doubts. When it comes to the desk work, brain work etc that is involved in programming, the work involves lots of stopping, starting and thinking - you can't really get into a trance-like state.

Isn't 'getting in the Zone' just another name for trying to enjoy the job and do it as well as you can? If you find your work interesting, you probably find that time passes quickly (this is sometimes called flow activity, where you are fully absorbed in what you are doing) and you have a sense of achievement when you finish a project - that, I would say, is the desk job equivalent of being in the Zone, and it's good enough for me. If you never get that feeling in your work, it may be the work itself doesn't suit you?