LongLines is a minor mode for Emacs that helps you edit text files with very long lines. Returns inserted by the user, which mark the end of each long line, are "hard" returns. The returns inserted by the filling functions, which prevent the lines from running off the screen, are "soft" returns. Long Lines Mode ensures that soft returns are automatically removed when the text is placed into the kill ring or saved to disk.
Note that the latest CVS version of Emacs [emacswiki.org] already contains longlines.