www.pixel-arts.org
www.pixeljoint.com
www.punaji.com
post your stuff there if you want real help with pixel art. they'll give you good critique and it'll really improve your skill level.
edit: don't worry about other programs either, mspaint has everything you need for pixel art. if you pm me I can give you a program to convert bmps from paint to quality gifs, with the option of saving with transparent bgs too.
edit2: I just looked through some of your stuff, you have potential but you really have to clean up your lines, and learn to aa. and watch out some of your stuff looks pillow shaded, try to stay away from that.