Free Music Archive

Free Music Archive offers music tracks that are safe to use in podcasts and other productions.  You can search songs or browse by artist and genre.

MorgueFile

MorgueFile is an online collection of royalty free photos.  They do not require attribution, or crediting their site for the photo, but they do provide url's for the image that I would use to cite the source just to be safe.

Pics4Learning

Pics4Learning.com is an image library specifically made with teachers and students in mind.  The images are free and safe to use and each image is accompanied with a short bibliography for proper citation.  You can also join the community by submitting your own pictures to share.

FreePhotos.com

FreePhotos.com provides royalty free stock photos for online use.  You can download high-resolution images and use  them in a project that is shared online.  Their one requirement is that you link back and give credit to their site whenever you use one of their pictures.