Free Online Office Tools

Google Docs

Zoho Suite

Think Free 

SpellJax - instantly spellcheck your text online

Adobe Buzzword

Twiddla  - Online whiteboarding.  Surf the net with friends while chatting and annotating.

Thinkature

Writeboard - online text documents

PDF on the Fly - create pdf documents easily with no download required.

Empressr: Another great online presentation tool.

Sliderocket: Online presentation tool

Prezi - online presentation creator

Tips: Interesting Ways to use Prezi in the Classroom

PhotoPeach - online story/slideshow creator