In Photoshop and Photoshop Elements use the mouse Scroll Wheel to zoom in and out.

Click on Edit> Preferences> General.
Then in the right-pane, click the box next to "Zoom with Scroll Wheel".
Finally, click on the "OK" button.

All of the other ways to zoom still work, but now your hand can stay on the mouse, if you wish.
I just discovered this and wanted to pass it on in case any are unaware.

When using any Brush Tool, I now keep one hand on the mouse and the other on the [ and ] keys to
adjust brush size.  This is really a very natural and fast way to control the brushes.

Don't forget Click-Shift-Click for really fast straight lines and the Space Bar to move around the image.