Process States in LaTeX with tikz

gistfile1.tex

\usetikzlibrary{arrows}
\begin{document}

\begin{tikzpicture}[->,>=stealth',shorten >=1pt,auto,node distance=5cm,
  thick,main node/.style={circle,fill=blue!20,draw,
  font=\sffamily\Large\bfseries,minimum size=15mm}]

  \node[main node] (B) {B}; %Bereit
  \node[main node] [above left of=B](L) {L}; %Laufend
  \node[main node] [above right of=B](I) {I}; %Inaktiv
  \node[main node] [below left of=L](W) {W}; %Wartend

  \path[every node/.style={font=\sffamily\small,inner sep=1pt}]
     
     (I) edge [bend left=30] node {Prozess starten} (B)
     (B) edge [bend left=10] node {hightes Prio} (L)
     (L) edge [bend left=10] node {Prozess stoppen} (I)
     	 edge [bend right=20] node[left] {Warten auf Ereignis} (W)
         edge [bend left=10] node {nicht mehr hoechste prio} (B)
     (W) edge [bend right=30] node[below=2mm] {Warteereignis eingetreten} (B) 
  ;
\end{tikzpicture}
\end{document}