Here is a list of links where you can download brushes, textures, etc. to use with Photoshop, Paint Shop Pro or whatever other program you choose to use. These resources are to be used on your graphic creations (signatures, layouts, etc).
The links marked with a red asterik [*] are considered great sources.
Photoshop Brushes
To learn how to install and use Photoshop Brushes, click here.
Swimchick *
Brusheezey *
PsBrushes
Hybrid-Genesis
Deviantart *
Fractured-Sanity
GetBrushes
Paint Shop Pro Brushes
To learn how to install and use Paint Shop Pro Brushes, click here.
Swimchick *
Deviantart *
Magitek-Designs
Pixelfresh
Miinc
LushBrushes *
Textures
To use textures, find one you like, right click and copy it. Now paste it on a new layer in your imaging program (paint shop pro, photoshop, etc), and lower the opacity, or change the layer effect (normal, screen, overlay, etc).
Swimchick *
Deviantart *
Livejournal Profile
CgTextures
TextureKing
DesignReviewer
Feel free to suggest other websites. All suggestions will be reviewed before being added to this list.