Jeffrey Selingo (The NY Times via Kairos News) sums up nicely how podcasts can be used in the K-12 classroom. One of his sources says,

"A podcast is like few other devices that a teacher can use in advancing a student's development," said Daniel J. Schmit, an instructional technology specialist in the college of education at the University of Nebraska at Lincoln and the author of "KidCast: Podcasting in the Classroom." "It teaches them to do research, to communicate in print, to speak effectively and grab attention with sound."

One reason podcasting is effective in the classroom, Mr. Schmit says, is that it can be used in every subject. Indeed, "Coulee Kids" is like a weekly variety show, running 7 to 14 minutes, with introductory music. The Nov. 18 podcast included discussions of photosynthesis, the difference between angiosperms and gymnosperms and a segment on adding integers. The Jan. 6 episode featured student interviews about bullying, a follow-up to a report on "20/20."