tikz-automaton.tex

\documentclass[12pt]{article}
\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{arrows,automata}
\begin{document}
\begin{tikzpicture}
\tikzset{vertex/.style = {shape=circle,draw,minimum size=1.5em}}
\tikzset{edge/.style = {->,> = latex'}}
% vertices
\node[vertex] (1) at  (0,0) {$q_0$};
\node[vertex] (2) at  (2,0) {$q_1$};
\node[vertex] (3) at  (0,-2) {$q_2$};
\node[vertex] (4) at  (2,-2) {$q_3$};
    %edges
    \draw[edge] (1.10) -- (2.170) node[midway, above] {$1$};
    \draw[edge] (2.190) -- (1.350) node[midway, below] {$1$};
    \draw[edge] (2.280) -- (4.80) node[midway, right] {$0$};
    \draw[edge] (4.100) -- (2.260) node[midway, left] {$0$};
    \draw[edge] (3.10) -- (4.170) node[midway, above] {$1$};
    \draw[edge] (4.190) -- (3.350) node[midway, below] {$1$};
    \draw[edge] (1.280) -- (3.80) node[midway, right] {$0$};
    \draw[edge] (3.100) -- (1.260) node[midway, left] {$0$};
\end{tikzpicture}
\end{document}

Use it in combination with the standalone document class! https://tex.stackexchange.com/a/51766/170682