I created a page for my students that includes my favourite online writing tools. We find it very useful:

Most important French searching tools:

Google Français - my favourite (click on français)
Startissimo - Multisearch engine for sites, images and music
Sympatico - most visited in French Canada (click on français)
Trouvez - meta-search engine
Toile du Québec - content from Quebec
Voilà - very popular in France
Yahoo! - most popular

Search engines for kids:

Kidadoweb
SitesPourEnfants.com
Takatrouver

Various tools:

1000Conversions
convert almost anything
Biographie.net
9767 biographies (3646 biographies in French)
Canada 411
search for a phone number
Classroom clipart (E)
over 10,000 free photos and cliparts
CPF French Software and Internet Address List
excellent resource for French as a second language
Cyberflag
flags, anthems, coat fo arms from around the world
FindSound.com (E)
search engine for finding sound effects on the Web
Google - Recherche d'images
search a picture on the internet
Guide de la Radio et du Live
live TV, radios ans webcams
Horlogeparlante.com
talking clock from around the world, count duration, ...
How Far is it? (E)
find the distance between the latitude and longitude of two places
Internet Moving Images Archive (E)
historical movies viewable online
Ivan Sarajcic's Flag Identificator (E)
identify flags according to their shapes, colors, ...
Images Canada
gateway to images of events, people, places and things!
Language Identifier
an online system that statistically guesses the language of some text
Librairie Renaud-Bray
bookstore with an excellent search engine
Minilien.com
avoid long broken links with this shorter link generator
PagesJaunes.ca
search for a business, a person, phone number, ...
RC-Médiathèque
collection from French CBC of audio and video documents
Reverse Lookup (E)
you have a phone number and you wonder whose it is
WebdoPresse
search for a newspaper (bottom right for language, continent, ...)
Yahoo! Cartes
search city maps and find directions