Audacity has been around for a long time and has for right or wrong been considered a very poor cousin to Garageband. Regardless of how it compares to other products Audacity is still a great tool for teachers and students and it is completely free. I came across these great tutorials that are primarily focused at creating podcasts but can be applied to any aspect of Audacity. Your students would be more than capable of following them with ease and they are a great starting point for staff who have little experience with Podcasting or Audacity. Check them out here.