Someone Dumb Down Textures for Me?

[Mamarazzi_2008]

I found some textures but I haven't the first clue in how and when to use them. Can someone give me a dumbed down step by step on how to apply a texture in photoshop CS2?
Also any links to some good textures to play with would rock.

[Saralonde]

Textures for Layers

I'm sure there are better tutorials, but here is one I did.

[Saralonde]

Here's another tutorial on flickr and one on the Coffeeshop blog.