background - What is this pattern called and how is it created?

I've seen this on many websites as a background but I can't seem to find a name for it or I can't seem to create it myself. If someone has done this, it would help a lot if you can give me some details.

Answer

Essentially that's called noise.

Basically there is a base color and then there's noise added to that color layer.

In photoshop you can do this with add noise filter.

Filter > Noise > Add noise.. ( Just like 1% or so.. just a hint of noise. )