I am releasing my minElo.exe utility tool for pgn files. It is used to extract only those games of a pgn file in which both players have an elo greater or equal to a user-specified value. The output file is separate from the original file, which is unchanged.
Example:
minElo alpha.pgn 2600
will create an output file outM.pgn that contains only those games in alpha.pgn where both players have an elo of at least 2600.
http://homepages.tesco.net/henry.ablett/jims.html