Apply Textures to your Graphics in Illustrator and Photoshop
This tutorial demonstrates the "Inside Out" texture collection, but the same techniques apply to all textures that come in Bitmap Tiff, Photoshop PSD, Jpeg, and Photoshop Brush formats.
(Such as Analog Halftones, Bad Photocopy, Bitmap Textures, Bitmap Textures - Fabric, and Time Machine texture collections)
1:30 > Adobe Illustrator: Using the "Opacity Mask" method
3:15 > Adobe Photoshop: Applying textures "non-destructively" using Layer Masks and Photoshop Brushes
More about using the Opacity Mask Method in Illustrator:
Even more ways to use textures in Photoshop & Illustrator:
(note: this video is a bit fast, so you may need to pause & rewind if you miss anything)