Not sure if my fellow expats were aware of this, but if you have had your Carnet for more than 2 years in Peru, you are allowed to vote in Municipal and Regional elections.
I do not know anything more that what the law states so if you need to figure out where to vote or what the process is you can call the ONPE (National Office of Elections and Processes) for more information.
Their phone number is:
ONPE (Oficina Nacional de Procesos Electorales)
(Artículo 7 de la Ley de Elecciones Municipales (Ley N° 26864). Law Number: 26864, Article 7.http://www.congreso.gob.pe/ntley/Imagenes/Leyes/26864.pdf
The law reads as follows: - Los extranjeros mayores de 18 años, residentes por más de dos años continuos previos a la elección, están facultados para elegir y ser elegidos, excepto en las municipalidades de frontera, siempre y cuando estén debidamente inscritos en el registro correspondiente. Para ejercer este derecho, el extranjero se identifica con su respectivo carné de extranjería.
Here is my "translation" of the law.
"Foreigners older than 18 years of age, residents with more than 2 consecutive years prior to the election, have the ability to elect (vote) and run for election, with the exception of border municipalities, provided they are properly registered. To exercise this right, the foreigner must show proof of his/her carnet."
I am voting for the first time but as a Peruvian, so with my DNI number, I have been allotted a specific voting area that I need to go to on October 3. Not sure how the process is for a foreigner, so you will need to call for more details.
Hope this helps.