Hexposure - This program allows you to change the text in an NES rom very easily using table (.tbl) files.
HomePage - http://home.sol.no/~kenhanse/nes

Tile Layer - Tile Layer is a very good tile editor for NES roms. This program allows cutting, pasting, and has mouse and GUI support.
HomePage - http://home.sol.no/~kenhanse/nes/

Graphics Inserter | Graphics Extractor - I had to use it this one to believe it, but these programs let you remove tiles from .nes roms, change them into .bmp files, edit them in the paint program of your choice, then insert the changed .bmp into the game!!! Excellent for graphics hacking!
HomePage - http://fly.to/vale

Mario Improvement - Create your own custom levels for Super Mario Bros. Tired of the same old, same old? Change it!!!
HomePage - http://www.geocities.com/SiliconValley/Bay/2628/

Mario 3 Improvement - Create your own custom levels for Super Mario Bros. 3. Tired of the same old, same old? Change it!!!
HomePage - http://www.geocities.com/SiliconValley/Bay/2628/

Final Fantasy Improvement - Edit and change the overworld and town maps in Final Fantasy. Another great Improvment title. Keep 'em coming!
HomePage - http://www.geocities.com/SiliconValley/Bay/2628/

MetEdit - Edit and change the levels for the Classic NES game, METROID!! Simply fun!!
HomePage - http://home.sol.no/~kenhanse/nes/

Zelda Improvement - Make your own Zelda maps... What else is there to say??
HomePage - http://www.geocities.com/SiliconValley/Bay/2628/

More to come soon!!