EDIT: Suggestion from ElMafias, to install gradients:
Simply go to your filters section click the arrow in the top right, click load gradients, and select your gdr file and you're set..
- GunWrath: Golden post. This is all his research, I am only posting to spread the information. Thank him.
- ElMafias: Suggestion to installing gradients easier.
This is where most GFX artists get free brushes, fonts, etc to use.