Flickr – Pictures, pictures, pictures! More pictures than you’ll ever need. Watch your licenses if you’re planning on using them.
KeepVid – Lets you download Youtube videos and others to your computer.
Picnik – Online picture editor with a good variety of editing effects.
Grooveshark – Free online music. I’m not sure how it’s free, but it’s great.
Animoto – An online slideshow tool that does all the work for you. Very quick, very easy.
WordPress – Clearly a good place to start blogging for free.
Twitter – Microblogging – blogging with less characters – a great place to meet and learn from other educators. Get some smart people around you and bathe in the wisdom.
Weebly – create your own website the easy way! Lets you edit with html as well.
Slideshare – Publish your own and view other people’s slideshow presentations. Great for ideas and information.
SlideRocket – Slick online presentation tool I would recommend over PowerPoint.
Screencast-O-Matic – Free, online screencasting tool for all your screencasting needs.
GoogleDocs – Online wordprocessor and so, so much more. Amazing for collaborating.
Dropbox – Free cloud storage. One of the greatest things ever.
TED Talks – presentations by all sorts of smart people on all sort of topics that are sure to inspire.
Stumbleupon – Delivers content based on your interests. Tends to waste enormous amounts of time.