Google Maps: How to zoom...
The esiest way to zoom in and out on a Google Map, is to use the Mouse Wheel (up for zooming in, and down to zoom out).
Sometimes this isn't possible (by default mouse wheel zoom is disabled for API usage, and it's hard to use a mouse wheel when you're on a laptop with no mouse!)
In this case you can double click with the left button to zoom in (I'm sure everybody knew this) - but you can also zoom out by double clicking the right mouse button.
(And if you are using a Mac Book, then tough luck as Apple are still insisting that a right mouse button is superfluous!!!) (...waits for flames from Mac Fan Boys...)


Yeah, I realise the mighty mouse does offer right mouse button - although it doesn't seem to work universally (Boot Camp / VMWare Fusion seem to have problems)
It's not much help when you are using the track pad though... (although I believe some of the latest MBP / AIR track pads allow you to use 2 fingers to right click...