This thread basically tells you resources to help you photoshop images.

Side Notes
-Links like this mean that they require registration.
-Links like this mean that they are broken/unuseable/temporarily unavailable/etc.

Image Hosting Sites
Host your images online so you can use them!

ImageShack - http://imageshack.us
Photobucket - http://photobucket.com
Tinypic - http://tinypic.com
XS.TO - http://xs.to/

Programs
Programs to help you make the image YOU want!

Photoshop CS3 Trial Version - http://www.softpedia.com/get/Multimedia/Graphic/Graphic-Editors/Adobe-PhotoShop-Trial.shtml
GIMP - http://gimp.org/
Paint.NET - http://www.getpaint.net/redirect/wp/index.html
Portal Graphics - http://www.portalgraphics.net/en/

Stock Images/Renders sites
Find the render you want to use for your signature with ease!

DeviantART - http://www.deviantart.com/
Planet Renders - http://www.planetrenders.net/
Stockxchng - http://www.sxc.hu/
Gamerenders - http://www.gamerenders.com/
Stock Photos | Shuttershock - http://www.shutterstock.com/ (*Payment is required*)
Anime/Manga Wallpaper - http://animepaper.net/
Free Photos Bank - http://www.freephotosbank.com/
Game Sprite Archive - http://www.gsarchive.net/index2.php
TextureKing - http://www.textureking.com/
Animekon - http://www.animekon.com/gallery.html
Grand Chase Picture Collection - http://community.webshots.com/user/AmaOcean
Anime Project Alliance - http://animepa.csusm.edu/galleries/index.htm
Anime Stocks - http://www.animestocks.com/
Advanced Anime - http://www.advancedanime.com/
4chan - http://www.4chan.org/
Otaku Forum - http://www.otaku-forum.net/
Boyis - http://www.boyis.com/html/
We-Love-Anime - http://www.we-love-anime.com/gallery/index.php
Animezen - http://www.animezen.net/
Virtualdesign - http://www.virtualdesign.tk/
Minitokyo - http://www.minitokyo.net/
HQP - http://hqp.free.fr/
Celebrity Scans - http://www.celebrity-scans.com/
Scan-tastic - http://www.scan-tastic.net/
ElegancePixified - http://www.elegancepixelfied.com/
Aethe Reality - http://gallery.aethereality.net/
Anime Art Books - http://animeartbooks.net/
Bubbleys - http://www.bubbleys.net/screenshots/
Digik - http://gallery.digik.net/
Ferricorp - http://www.ferricorp.com/
Graceful Lament - http://graceful-lament.com/gallery/main.php

Tutorials
Read tutorials to help you with making your own!

Photoshop Tutorials - Good-Tutorials, PS Lover, Photoshop Tutorials, Tutorialized, PixelFx, Shadowness, Spoono, Phong, DesignsByMark, Team Photoshop, Icon Factory, W3Tutorials, Fry Tutorials, Absolute Cross, Sigsource, Tutorialized (Paintshop Pro), Screaming Art, Daydream Graphics, Polykarbon,Graphics Void

GIMP Tutorials - Gimpology, Gimp Talk, Gimp.org.

Paint.NET Tutorials - Paintdotnet

General Tutorials - DeviantART

Brushes
Use specially made brushes to help boost the professionalism of your signature!

Photoshop Brushes - Deviant.ARTAnnikavon, VeredGF, Pretty Brush, Policeman, Echoica, Rebel Heart, MagicBox, Tere-Art, Qtone, Cirratus, Angelic-Trust, Nocturna, AnotherBrushResource, MisprintedType, Magurno

GIMP Brushes - Project~GimpBC, Deviant.ART

*Paint.NET Brushes - Paint.NET Custom Brushes,

*Paint.NET requires a Plug-in to download brushes. Here's the link: Click Me!

Plug-ins/Effects
Use the effects to create/manipulate wonderful things!

Photoshop Plug-ins/Effects - Adobe Photoshop

GIMP Plug-ins/Effects - Gimp Talk

Paint.NET Plug-ins/Effects - Paintdotnet

Fractals/Abstract/Apophysis/C4D
Enhance your signature with beautiful abstract designs!

Planetrenders - http://planetrenders.net/renders/index.php?cat=7

Fonts
Use creative and fancy writing!

Dafont - http://dafont.com
Blambot - http://www.blambot.com/
Identifont - http://www.identifont.com/
Myfonts - http://myfonts.com/WhatTheFont/
Misprintedtype - http://www.misprintedtype.com/
Acid Fonts - http://www.acidfonts.com/
Abstract Fonts - http://www.abstractfonts.com/
Chank - http://www.chank.com/

It's not done yet, and I would love it if people contributed to this. =/

And thank you to all contributers!
 

And please post if I've given a broken link.

Credit>Ruuka~

No when i try to download it I can't open it... I"m attempting to download the installer they offer btw.

 

For Paint.net brushes, You install the pluggin from here:

http://paintdotnet.forumer.com/viewtopic.php?f=16&t=23093&sid=0f3cf67c1c09b6a00a3fd1602ad97fea

and then you save png images into a folder in my documents, you can get those from here:

http://paintdotnet.forumer.com/viewtopic.php?f=12&t=23095

And actually, for lots of other plug-ins and effects just browse the forums here:

http://paintdotnet.forumer.com/viewforum.php?f=16

Oh, and here's the forum link to tutorials:

http://paintdotnet.forumer.com/viewforum.php?f=15

That should fill in some blanks~

O.O

*uses Luna's links*

I need to check on them first =3 

Credit>Ruuka~

Adobe brushes (They work on GIMP since 2.4)

QBrushes.com

Obsidian Dawn (They got good brushes, but the file size is big)

For GIMP tuts, what iJustin mentioned (I also go there if dont know what to do)