Colour Scheme Chooser :

An on-line function that allows you to see what colours mix and match. You can create harmonious color schemes, preview and save them .

http://www.siteprocentral.com/html_color_code.html 

Boinc :

Berkeley Open Infrastructure for Network Computing hosts a number of projects that use your computer's idle time to perform calculations to help scientific investigations

http://boinc.berkeley.edu/

Stellarium:

Stellarium is free software which renders realistic skies in real time . It is available for Linux/Unix, Windows and MacOSX

With Stellarium, you really see what you can see with your eyes, binoculars or a small telescope.

http://stellarium.free.fr/

Windows help sites

http://www.annoyances.org
Annoyances.org claims to be the most complete free web resource ever assembled for Microsoft Windows

http://www.dougknox.com/
Fixes, tweaks and tips for Windows users

Photoshop help sites

http://www.myjanee.com/ps.htm
Well regarded resource with links to other sites

On-screen Keyboard

http://www.lakefolks.org/cnt/index.htm
Free software which enables people with certain disabilities to type using only a mouse. Available in lots of different languages.

Child Protection Software :

None of these are a substitiute for proper parental control. Other software is available. Your ISP may also provide on-line filters.

Cyberpatrol http://www.cyberpatrol.com/

Netnanny http://www.netnanny.com/index.html

Cybersitter http://www.solidoak.com/