the EASA recommendations
I am in exactly the same boat as you
I have been informed by a JAA examiner that you can instruct on the PPL with an FI rating but not for financial reward under the new EASA recommendations. The examiner also told me that you will need the CPL theory or ATPL theory to teach for financial reward but not the CPL Practical course.
I am going to do the CPL Theory and the practical as I think it will help me become a better instructor, and as I will be hoping to teach students for money I would prefer to teach them from the stronger standpoint of holding a full commercial license.
I am currently training in Florida and also doing my FAA instrument rating whilst I am here, to gain as much experience I can through these training periods as I feel the more experience you have the better the pilot and therefore the better the instructor you can become.