The treatment depends on a few things - how aggressive it is, whether or not it has gotten out of the prostate, and possibly your age. If you are a lot older than me, it could be that it is not worth treating because something else will kill you long before the cancer will. That may be a bit blunt, but it's how the docs have to think sometimes.
When I had it, I was 50, it was still in the prostate and was moderately aggressive. So I had three options, surgery, radiotherapy or be in a coffin at around 65.
There is another form of treatment developed at St George's hospital in Tooting, but it is new (it was still being trialled when I was diagnosed) and probably only used on selected patients. It's a bit like immunisation, so you might want to talk to your doc about it, and remember you may not be suitable for the treatment.