You've downloaded new pattern and you want to load it to yous Adobe Photoshop, read this tutorial.
- Put the .pat file you've downloaded into the folder /Users/{username}/Library/Application Support/Adobe/Adobe Photoshop CS3/Presets/Patterns (on mac OS X) or C:\Program Files\Adobe\Photoshop\Presets\ (on Windows) .
- Then open your Adobe Photoshop, active Paint Bucket Tool,