This applet displays the wave functions (orbitals) of the hydrogen atom (actually the hydrogenic atom) in 3-D. Select the wavefunction using the popup menus at the upper right. Click and drag the mouse to rotate the view.
This applet displays real orbitals (as typically used in chemistry) by default; to display complex orbitals (as typically used in physics) select "Complex Orbitals" from the popup menu in the top upper right.
You can also view combinations of orbitals.
Molecular Orbitals Applet.
1-Dimensional Quantum Mechanics Applet.