I have worked with several production companies and I am on my second where I am a full time paid employee and I would just have to say that I have yet to see any production company anywhere hire a PA for pay. Everywhere I have been, worked with, and heard of takes PA's as interns only, simply for the fact that competition is so stiff. Think about it, why would you pay someone an hourly rate if you can just get a college student who is just as eager to do those things for free? It doesn't make sense. Maybe things are different around the world but in my neck of the woods that is the reality.
Now that being said there are ways to get into a production company. You have to have experience. This isn't hard to get either. Look at your local film guide for Gaffers if you want to light, Camera operators if that is you bag, or anything else that you would like to do. Pick a concentration, and then start e-mailing as many people as possible and ask if you can apprentice them for free. Ask if you can do it in your spare time to get some experience. Be warned that their are people who will take advantage of you so you have to be careful. Start putting yourself out there more, make connections, if people call you up and ask you to work and your confident that you can do the job then ask what the going rate is.
Once your skill is up start looking for that production company that is looking to fill a position in whatever you choose to study. Then apply. This is the only way I know of getting hired at a production company as an employee. Perhaps somebody else has different tips. Good luck and let us know what happens.