overlapping nodes

How to solve the problem of overlapping nodes? I want the below of n1.

\usetikzlibrary{positioning}
\tikzset{every node/.style={blue,rounded corners}}
\begin{tikzpicture}
\node[draw,fill=yellow] (n1) {
\begin{minipage}{5cm}
alignment of nodes

with \verb|minipage|

long text

fourth line
\end{minipage}
};
\node[draw,fill=orange!25] (n2) [below =1cm of n1.west,anchor=west] {below node};
\node[draw,fill=green!25] (n3) [right = of n1.north east,anchor=north west] {
\begin{minipage}{5cm}
right node

with \verb|minipage|

tirth line.
\end{minipage}
};
\draw[<-,>=latex,red,very thick] (-.3,-1) to [out=0,in=180] (1,-1.5) node[right] {problem here.};
\end{tikzpicture}


i need below of n1.

-
I myself decided. \node[draw,fill=orange!50] (n2) [below = of n1.south west,anchor=west] {below node}; –  Regis da Silva Jul 7 '11 at 1:51

You should use below = 1cm of n1.south west instead of just .west if you want the node to be placed 1 cm below the bottom edge of the node. If you just write .west, the new node will be placed 1 cm below the middle of the other node.