I actually just answered a question for someone who was curious about Project Charter Templates and the rest of their question included things like PIDs, SOWs, and Project Proposals, and I decided that those are things that I don't know much about but would be very interested to learn about. So if you have any basic information on these topics or any references then I would be very appreciative.
A number of good templates are available at the UK OGC site. These are geared towards the PRINCE2 standard but should work for most cases.
I am PRINCE2 certificate. I could give a bit of clearance for PIDs and other PRINCE2 documents but I am not sure how much that would be of help. What I mean is that a template itself is nothing but a few lines of reminders what you should do. If you use a template that is some methodology's standard it will not be very much helpful because it's the methodology that makes the difference.
Even if PID is presented to you, the rest of the steps for successful project laying behind PRINCE2 (per say) will be those that will help you.
Anyway... if you are interested in PRINCE2 specifically, say so and I will try to help you with what I am able to.