The Salary
Range is about £18K to £80K.
Depends on your age and experience, and all the other stuff Van B mentioned. It also depends on current legislative changes, believe it or not. Y2K and EMU, for example, generated a high demand for programmers.
Avoid languages you can learn at home, there are too many home-grown coders for this market. SQL Server is what I would call entry level for truly skilled, in demand IT jobs.
Once you get a job, take advantage and learn all the skills you can only learn in industry - different platforms and languages, business skills and concepts. That sets you apart.
Finally, don't stand still. You can lose your value by being "comfortable" where you are.
That's the difference between low and high paid IT professionals.
BatVink