In the layers palette, you can link different layers to each other. This will allow you to move them together (when you are on the "V" moVe tool). The chain of love is located to the right of the seeing eye on the layers palette. Each layer has the option of linking. Just click on the layer you want to be on and then click on the link box and pick other layers in the palette to link to by simply clicking on their link box; this will link those layers to this layer.
Linked layers will go off of what layers are linked to the currently used layer (even if there are different link strategies going on). So the layer you are on, when you move it, the linked layers will follow.
You can unlink by clicking the link box again. You can link fast by clicking and dragging down the entire row (you can also unlink this way).
A handy little tool you can use is the arrange layers features in the options bar when on the move tool. When layers are linked you can center layers on each other. Just look at the chains of love to figure out how you want to align your layers (such as "aligning vertical centers" "aligning edges" etc.). You can easily center text for example by linking it to the background layer (layer which covers the entire document) but you may have to make sure the background layer is selected in the palette so you can align the text (or other) layer with it.
You may try and hide a layer or even try moving a layer but nothing happens; this is because you need to be aware of the actual layer that is selected in the layers palette. It happens to all of us so, there there now..don't cry. So make sure you select the layer you want in the palette (or right click with the move tool and select from there...or have 'auto select layer' option on..(this is a long parentheses..))
It's essential to know the basics of html layers usage!
Linking is great for moving certain layers together and if you can't think of a situation when you can use them, then you definitely need to start designing (with layers)! You can also use layer sets (folders) to move layers together.
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