Lesson Plans as Intellectual Property

Check out the most recent blog post from Tech Dirt.  The author sums up a trending lesson plan controversy when he the post states, "Some school districts are upset that the teachers are selling lesson plans, believing they deserve some of the "cut". 

An article by the National Education Association details the legality of intellectual property.  According to the National Education Association, one of the largest labor unions in the country representing teachers in the public school system, much of the work created by teachers does in fact belong to the school district.  Thanks to the Copyright Act of 1976, materials created as part of one's job duties belong to the employer.

Personally I think this is ridiculous.  Perhaps there should be a clause that materials created by a school's employee may not be sold to other employees of the same institution, and must be freely shared upon request.  But then, would this allow the lazy underachievers to simply ride the wave of another teacher's dedication?  

What do you think?  Comments are appreciated!