Much of this gotten from Ptoing at Pixelation with some editing by me.


Tools

Drawing Programs
GraphicsGale (http://www.humanbalance.net/gale/us/) - timedware and freeware (lite version)
A very good pixel art program that allows frame to frame animation and layers.
There is both a freeware and shareware version. The main difference being the shareware version
allows you to load and save GIFs (handy for animations outside of DM)
I use this one and it's my favorite.

MSPaint Walkthrough (http://fay.iniminimo.com/paint.html) - bundled w/ Win OS
If you're new to MSPaint, this is a good place to start.
I miss a lot of features like a full palette, frames and layers when using paint,
but you've probably already got it and it'll work for pixeling.

the GIMP (http://www.gimp.org/) - freeware
A free, open-source photo editor, capable of damn good pixeling.
It's very flexible and customizable and comes with a lot of good features
Some find the interface difficult. I switched from this to GraphicsGale because
it lacks good animation features.

Adobe Photoshop (http://www.adobe.com/products/photoshop/family.html) - sell a kidney (eval ver. available)
A premiere digital art program with many features and quite capable of creating great pixel art.
Familiar interface and LOTS of capability. Very expensive, but available as timedware.
Again, not so great at the animation.

Some other drawing programs that I haven't tried (yet) -

ProMotion (http://cosmigo.com/promotion/index.php) - medium price (evaluation ver. available)
Comes highly recommended by some who would know.

ProDigital Painter (http://www.squirreldome.com/cyberop.htm)
ArtRage (http://www.ambientdesign.com/artrage.html)
GraFX 2 (http://www.eclipse-game.com/?dat=7)

File Conversion
Easy Graphic Converter (http://www.etrusoft.com/graphic-converter/) - freeware

Screen to Pic/Video Capture
Capture Pad (http://www.capturepad.com/) - shareware

Fonts
Bitmap Font Utility (http://www.stefan-pettersson.nu/site/bmpfont/) - freeware
A program that allows you to build your own bitmap fonts and save them as a pic.
Some premade fonts here: http://www.speccy.org/remakesgraph/temp/fuentes/fuentes.htm


Pixel Tutorials

General

Tsugumo - (http://petesqbsite.com/sections/tutorials/tuts/tsugumo/)
One of the best all around pixel tutorials; Best to go through all the chapters.
Natomic (http://www.natomic.com/hosted/marks/mpat/)
A good starter/all-around tutorial
PixelZone Tutorials (http://pixel-zone.rpgdx.net/shtml/tutorials.shtml)
A collection of pretty good pixel tutorials (including some mini tuts)
Derek Yu (http://derekyu.com/extras/pixel01.html)
A great 10 part tut on pixel basics and figure drawing.

More Specifically
SpriteArt (St0ven) (http://www.spriteart.com) -
Lines Tutorial (http://www.spriteart.com/tutorials/01_lines.html)
Dithering (http://www.spriteart.com/tutorials/01_dither.html)
Antialiasing (http://www.spriteart.com/tutorials/01_AA.html)
Reverse Antialiasing (http://www.spriteart.com/tutorials/01_AA.html)
Ambient Lighting on a Sphere (http://www.spriteart.com/tutorials/02_ambient_sphere.html)
Ambient Lighting on a portrait (http://www.spriteart.com/tutorials/02_ambient_sphere.html)
RPG Sprites (http://www.spriteart.com/tutorials/02_rpg_hero.html)
Small and larger.
RPG Enemies (http://www.spriteart.com/tutorials/03_rpg_enemy.html)
Drawing from a silouette.
RPG Monsters (http://www.spriteart.com/tutorials/04_rpg_summon.html)
Building a silouette from a line skeleton and building depth with color.
Semitransparency (http://www.spriteart.com/tutorials/01_trans00.html)
Scanlines and a holographic effect (http://www.spriteart.com/tutorials/01_interlace.html)
Gas-13
Antialiasing by Nemesis42 (http://gas13.ru/tutorials/aa/)
Matriax (http://www.speccy.org/remakesgraph/tutoriales/tuto.htm)
Shiny Surfaces (http://www.speccy.org/remakesgraph/tutoriales/reflect/ ingles/reflecti.htm)
Solar Rays (http://www.speccy.org/remakesgraph/tutoriales/rayosol/ rayosoli.htm)
Aging your Pixel Art (http://www.speccy.org/remakesgraph/tutoriales/estados/ estadosi.htm)
Mozco
Metallic Objects (http://www.tcp-ip.or.jp/~s-iga/tips/2-3metallic_objects.html)
A good tut on the shiny!

Isometric
Zoggles (http://www.zoggles.co.uk/asp/tutorials.asp?show=index)
Pixelfreak - http://www.pixelfreak.com/tutorial/
RhysD (http://rhysd.syntesis.org/tutorial/)
Pixel NascImpact (http://pixel.nascimpact.com/tutoriaux.php)
Basic Iso by Gunstar Red of Gas-13 (http://gas13.ru/tutorials/iso/)
Isometric pool by Matriax by way of Gas-13 (http://gas13.ru/tutorials/pool/)
SpriteArt.com
- Iso tiles in 2:1 ratio (http://www.spriteart.com/tutorials/02_iso_2to1.html)
- Iso tiles in 1:1 ratio (http://www.spriteart.com/tutorials/02_iso_1to1.html)
Matriax on Converting 2d to iso (http://www.speccy.org/remakesgraph/tutoriales/reflect/ ingles/reflecti.htm)

Hope these help.
Please, add some more and add your own opinions about these!