just use this header with your tex files and you get pdfs that are suitable for your kindle
\documentclass[12pt,a5paper,openany,oneside]{book}
\usepackage[a5paper]{geometry}
\usepackage[pdftex,pdftitle={book title},pdfauthor={Doe, John}]{hyperref}
\usepackage[pdftex]{color,graphicx}
\usepackage{graphicx,textcomp,booktabs,amsmath}
\usepackage{mathptmx,courier}
\usepackage[scaled]{helvet}
\usepackage{totpages}
\usepackage{amssymb}
\usepackage[utf8]{inputenc}
\textwidth 128mm
\topmargin -15mm
\textheight 175mm
\evensidemargin -15mm
\oddsidemargin -15mm
\begin{document}
%insert your text here
\end{document}