Why should this be included in the repository?: This is the GNU spell checker. Utilized heavily among emacs users and probably others. I'm honestly surprised that its not yet available.
Is it Open Source (yes/no): Yes
How many users do you anticipate will use this software?: Quite a few. Emacs is a popular editor.
Link to source tarball/zip file: ftp://ftp.gnu.org/gnu/aspell/aspell-0.60.6.1.tar.gz
Should also add the dictionary packages to make it usable. All are available at ftp://ftp.gnu.org/gnu/aspell/dict/0index.html