Louis, it's all about testing, testing, testing, aka "open competitive exams." I don't know about any other municipality or state, but I once went for a Department of Labor (New York State) position. This was a phase I open competitive exam with about 1,500 other applicants. I believe even though it was posted as "open competitive," you still had to have had a bachelors degree by the date of the exam, and be able to prove it. I passed, then went on to phase II. Here, you had to score a certain percentage to be passed on to phase III. Although many weeks later I found out I made a "good" score of 88.9%, that still wasn't good enough, apparently. Some parts of the test were personality-oriented, some parts communication-oriented, some "general-knowledge", and some quantitative. The exam contains some traditional multiple choice questions as well as some bizarre "follow the directions then answer" intructional inventories. It didn't really seem that hard to me, yet I still didn't pass on.
I found later that some of the most innocuous and seemingly-obvious questions are the ones that they want you to answer a certain way. The most "obvious" answers aren't necessarily what the testers have in mind, depending on the particular position you're going for.
I did, however, work in quasi-governmental research institutes, which are probably easier to get into since they are not as competitive and they focus mainly on interviewing rather than on lengthy testing (although some tesing IS involved, it's not to the extent as regular civil service positions.) Also such institutes, "authorities," or "commissions" might even pay you much better albeit with less benefits.
I know for the U.S. Govt, there's also a very lengthy application process, as well as testing for certain "GS" levels for certain "appointments". (At least this is how it used to be. It could've changed by now.)
I encourage you to check the library for reference books that detail ways of securing government jobs. They have loads of info. Also check the net if you haven't done so already.
PS., I'll also add you to my respected users list as soon as I find out how to do so.