For Pixel Art I suggest not using Paint. It doesn't have a "Show Grid" option. Photoshop is decent, but not made FOR pixel art and as such you'll find yourself using some inpractical tools.
I suggest Graphics Gale, and it is especially good for animating as well. Supports frames just like Photoshop and has some more detailed tools for when you want to try something diff.
http://www.humanbalance.net/gale/us/