A long time ago I stumbled upon this site when googling various things like How to become a Prison officer etc.
Ok the inside information is not free but believe me you do get you monies worth.
Give it a try:
[Only registered and activated users can see links. ]
I recently attended a one day course on How to become a paramedic and was pleasently surprised at the mass of info I was given.
They have a whole host of packs on many careers so take a look.