Web 2.0 sites allow the sharing of all kinds of media - photos, music, videos, audio files.

Photos

Flickr lets you upload, label, tag and organize your photos, share them, copyright them with Creative Commons, create and join groups, follow individuals, and search for subjects. Flickr is currently owned by Yahoo!
http://www.flickr.com

For example, Branka posted photos of TIMAC here
http://www.flickr.com/photos/branka_m/sets/72157601606944811/

Picasa is another photo sharing site with similar capabilities, owned by Google.
http://www.picasa.com

Video

YouTube is the best-know video sharing site in the world!
http://www.youtube.com

Google Video is another video sharing site
http://video.google.com

TeacherTube hosts videos related to education. It seems to be growing, and is a good place to upload your education videos because it is less likely to be blocked by schools.
http://www.teachertube.com

For example, here's a video about how to use the Elmo document camera
http://www.teachertube.com/view_video.php?viewkey=3f823ae1d2742f879422&page=&viewtype=&category=&action=addfavour

Another example, Dave Sconda posts his video on YouTube and then embeds them in his Web page
http://www.englishmeeting.com/esl_video_lessons_page.htm

Ustream is a site where you can live stream your video. More and more people are streaming their presentations, meetings, or just going online to chat via video.
http://www.ustream.tv

Here is an example of a presenter Ustreaming her presentation, so that people who aren't present can watch and participate in the live chat. Then the video is saved so that anyone can watch it afterwards. It can also be posted on a blog or somewhere else.
http://www.ustream.tv/channel/edtechtalk


Books


Shelfari lets you share what you're reading with others, and keep track for yourself. You can add friends and join groups.
http://www.shelfari.com/

Library Thing is another site for creating and tracking your library. It has thousands of members, and you can find other people who like the same books you do, and see what else they're reading.
http://www.librarything.com/