The EarthBound Sprite Editor is cool. Download it here. Make sure to read the FAQ that comes with it. Okay, bye.

NOTE: If you have problems getting the editor to work, you need to run the program from DOS. If it works but you can only see the sprite and some colors, no toolbar, then it's not loading the data file right. You should run the prog from DOS, and if you don't know how or can't get it to work, try getting the EBSE Front End from here. I won't respond to emails about getting it to work, so if you can't get it to work, do what I've said above or ask on the PK Hack message forum.