For February 2010 you can download the following articles for FREE even if you are not a member of NSTA. Remember, if you are a member, you can access articles from all of the journals- not just the one you subscribe to.
Science & Children (elementary): Turtle Girls
Science Scope (middle school): Unit Pages: Differentiation for 200 Students
The Science Teacher (high school): The “Green” Root Beer Laboratory
Science for All 