The product formerly known as PixelMonkey has been renamed SpriteMonkey, and can be found here at the Impending website.

Since that product is a paint program, of sorts, it is being extended to work with larger images, and to better support limited color palettes, layers, animation, and transparency. PixelMonkey shall be reborn as a true pixel art paint tool, while SpriteMonkey is being developed to specifically support sprite sheets.

More information on PixelMonkey will be released here at this site address, while you can hop on over to http://www.impendingstudios.com/spritemonkey/ for information on the sprite-sheet editor.