This is a progression from the NES Viewer utility. It's a tile editor written in Python, specifically for creating graphics for NES ROM's (and maybe later for editing graphics directly in ROM's). There are already programs for doing this, but I haven't found one which works in Linux. The code turned out to be pretty hackish and ugly in parts, due to my unfamiliarity with PyGTK. It is fairly unfriendly to use, but it is usable for simple projects.
Feel free to use the program and its source as you wish. Instructions for use are in the file "readme.txt" included in the tarball. License for use is a modified BSD license. This is alpha software. Known bugs and limitations are included in the readme.txt file, and there are probably many more. Changes from version to version are listed in the changes.txt file.
UPDATE: I've tested it and it does work in Windows, assuming all the right libraries are installed. Your desktop will need to be in 16-bit color mode, due to the stupid way I wrote it. Also, it seems to crash when loading very large files (e.g., Castlevania 3). My suggestion is to break up the CHR-ROM into different segments and edit them separately (or use a better tile editor), as I'm not planning on updating anytime soon.
Download Nestile v0.2.0