I am aware that this is an old question but since I arrived here looking for answers myself I thought I might share my findings.
The bleed can be added using the crop package. The way it works is that you define the page size you like for your final printed material as normal, e.g. using "a4paper" or "letter" in your documentclass command, or use geometry for custom page sizes.
In the document preamble, after you have specified the page size, you load the crop package and define the size of the page with the bleed. The size of A4 paper is 21x29.7cm so after adding 3mm (the typical bleed recommended by printeries) to each side the dimensions of the output should be 21.6x30.3cm.
\documentclass[a4paper]{article}
\usepackage[
% set width and height to a4 width and height + 6mm
width=21.6truecm, height=30.3truecm,
% use any combination of these options to add different cut markings
cam, axes, frame, cross,
% set the type of TeX renderer you use
pdftex,
% center the contents
center
]{crop}
\begin{document}
\title{Bleeding edge test}
\maketitle
A 3 mm bleed on an a4 paper.
\end{document}
Of course, the 3mm bleed on each side is thought as the area onto which the printed figures or colored areas are supposed to extend. Even though your content should only extend 3mm from the page, you may want to define the width and height in crop as the dimensions of the print medium. E.g. if you are printing an A4 sized document with 3mm bleed on an A3 paper, you should make your content extend 3mm beyond the A4 dimensions but define the A3 dimensions as the width and height in crop.
\documentclass{...}and ending with\end{document}. – May 29 '14 at 14:34\usepackage{crop}and for example http://tex.stackexchange.com/questions/171459/svmono-and-real-page-dimensions/171480#171480 how to apply it... – May 29 '14 at 14:38\usepackage[paperwidth=21.5cm,paperheight=30.5cm]{geometry}before\usepackage[...]{crop}if I remember the papersize of A4 correctly. – May 29 '14 at 14:55