The styling is based off of Facebook's emoji, and most colors derived from flatuicolors.com. So while I remade them in Illustrator, all cred goes to everyone else.
To install using the sprite sheet:
Upload the sprite sheet to your server.
Login to your ACP, and on the homepage, click Smilies.
Click Add New Smilie at the top.
Now fill in the appropriate information:
- Title: Name of smilie
- Text to replace: What typed text = which smilie
- Image replacement URL: The URL of the sprite sheet, wherever you uploaded the dang sheet.
Here is an example of what mine looks like, now just use the sprite position to change which sprite will be used. The sprite is displayed in the top right.