The web site of NoSoftwarePatents.com presents strong arguments why patents will badly damage the software industry. Copyrights are an appropriate mechanism to protect source code. Patents are for unique inventions, not the evolutionary progress that characterizes the progress of software.
Slashdot highlights the appeal from three of the key leaders of the Free and Open Software movement: Linus Torvalds of Linux, Monty Widenius of MySQL and Rasmus Lerdorf of PHP. Patents prevent progress.