How to create this grunge texture effect
How can I achieve this kind of background in Photoshop? Seems like a noise/paper pattern.
You can't really achieve a photorealistic paper texture by simply messing with noise in photoshop. Your best bet would either be in using one of free stocks or scanning the paper sheet yourself :)
If you'd like to have a paper-like texture then try to create noise, apply motion horizontal blur, do the same again, apply 1/4th of that to the motion vertical blur, add a bit of regular noise, blend everything together with significant degree of transparency.
But still it won't be as good as using real paper texture. Especially when you can obtain paper textures for free :)