This is a really neat podcast I used way back when we were doing our unit on the Solar System. It is from pbs...and is a podcast of different scientists making a pitch for each of their favorite planets (and they even throw in some other minor bodies). I had the students to research their own "favorite" and compose either a Photostory or PowerPoint presentation "commercial." I have the link to the podcast posted below:
"What's Your Favorite Planet?"
"What's Your Favorite Planet?"