this: http://www.fastgraph.com/makegames/3drotation/
is probably what you're talking about.
But if you're talking about a rotation about the three axes; then these are what you want:
$X = \left(\begin{matrix} 1 & 0 & 0 \\ 0 & \cos(\theta) & -\sin(\theta) \\ 0 & \sin(\theta) & \cos(\theta)\end{matrix}\right)$
$Y = \left(\begin{matrix} \cos(\phi) & 0 & \sin(\phi) \\ 0 & 1 & 0 \\ -\sin(\phi) & 0 & \cos(\phi)\end{matrix}\right)$
$Z = \left(\begin{matrix} \cos(\psi) & -\sin(\psi) & 0 \\ \sin(\psi) & \cos(\psi) & 0 \\ 0 & 0 & 1\end{matrix}\right)$
you just need to multiply them together in the correct order (i.e. reverse of the order which you perform them.
i.e. Rotation about X then Y then Z, or $R_{xyz}(\theta,\phi,\psi) = R_z R_y R_x$
which gives you this guy:
$R_{xyz} = \left( \begin{matrix} \cos(\phi)\cos(\psi) & \cos(\psi)\sin(\theta)\sin(\phi)-\cos(\theta)\sin(\psi) & \cos(\theta)\cos(\psi)\sin(\phi)+\sin(\theta)\sin(\psi) \\ \cos(\phi)\sin(\psi) & \cos(\theta)\cos(\psi)+\sin(\theta)\sin(\phi)\sin(\psi) & \cos(\theta)\sin(\phi)\sin(\psi)-\cos(\psi)\sin(\theta) \\ -\sin(\phi) & \cos(\phi)\sin(\theta) & \cos(\theta)\cos(\phi)\\ \end{matrix}\right)$