FREE Photoshop Patterns

Photoshop patterns are in ".pat " file format. They can be opened by either photoshop CS or Elements.
This artist, who names Shelby Kate Schmitz, provides plenty of free patterns for both personal and commercial designs. http://graphicssoft.about.com/od/photoshoppatterns/ss/sksplaidpat.htm

To use patterns (.pat files),steps are outlined as below:

1. download the desire pattern ( in ". pat" format)
2. open a new layer
3. click "create new fill/adjustment layer" below the layer panel
4. click "pattern"
5. click square with pattern fill (the one with colourful pattern) 
6. click a double arrows right next the list of patterns
7. click the option " load patterns" 

Then, you can create something like this, http://lavandalu.deviantart.com/gallery/#/d55nrx1
For more free stuffs from Shelby Kate Schmitz, please check this list http://graphicssoft.about.com/sitesearch.htm?q=Shelby+Kate+Schmitz&SUName=graphicssoft

Reference: http://www.heathrowe.com/photoshop-patterns-loading/