Another good way to break into the field is to work with a contract employment agency. They are often listed in the yellow pages or in the Sunday paper. They have job listings all over the country and also have phone numbers for agencies in your area. Pay scales vary according to region and segment of the market. I can only tell you what a good writer can expect to make in high-tech Southern California.
Overtime is generally negotiable.
Make sure that you ask for enough money. This is the capitalist market. Nobody will give you something for free. If you feel that the wonderful world of technical writing is for you, try some of my suggestions. Good luck and happy writing.