Downloading and Using Brushes

Once you've found a site with brushes you like, download them. (You may need to unzip them).
In Paint Shop Pro, click File >> Import >> Custom Brush. Find the folder they're saved to and then import, to use your new brushes simply click on the basic paint brush tool and select the brush you want. If the brush toolbar isn't showing up go to View >> Toolbars and tick the 'Tool Options' pallet.