OK.. so you have a computer but you don't fancy buying office tools like word processor, spreadsheet, database etc... OR you don't have enough free space... OR you want to be able to access your work from any internet PC.
WORD PROCESSORS
Zoho Writer (http://www.zohowriter.com)
Writely (http://www.writely.com)
Rally Point (http://www.rallypointhq.com)
SPREADSHEETS
Zoho Sheet (http://www.zohosheet.com)
Google Spreadsheet (http://spreadsheet.google.com)
NUM SUM (http://www.numsum.com)
PRESENTATION TOOLS
Thumbstacks (http://www.thumbstacks.com)
Zoho Show (http://www.zohoshow.com)
ORGANISERS AND CALENDARS
Google Calendar (http://calendar.google.com)
Kiko Calendar (http://www.kiko.com)
Zoho Planner (http://www.zohoplanner.com)
DIAGRAMS AND DRAWING
Gliffy (http://www.gliffy.com)
Picnik online photo editor (http://www.picnik.com/)
DATABASE
Google Database (http://base.google.co.uk)
MISCELLANEOUS
Online Paper CD Case (http://www.papercdcase.com/)
Send an SMS FREE to USA/Canada (https://www.vazu.com/)
Large File Transfer via E-mail (http://www.yousendit.com/)
Publish Information on WWW Instantly (http://www.shorttext.com/)
SurveyMonkey Free Online Survey Maker (http://www.surveymonkey.com/)
Zamzar Free Online File Conversion (http://www.zamzar.com/)
Live Documents online Office Suite (http://www.live-documents.com/)