Anti software patent video is worth a look
Groklaw points to a video on a site of the Foundation for a Free Information Infrastructure that explains why software patents are a bad thing. I tend to agree. It was created in response to the EU's current efforts to allow software patents. (Hence the "long a" "patent" in the video.)
Software patents are allowed in the US, but are very controversial. They are often granted for things that many feel are not original or worthy of patent protection. And many feel they result in code chill and stiffle innovation, rather than encourage innovation.