By free software I mean software that doesn't cost anything i.e. free as in beer. Many of the programs are also open source and therefore free as in speech as well.
Image software
Gimp
Gimp is an image editing program similar to Adobe Photoshop or Paint Shop Pro. You can use it to improve photographs, create artwork, compress photographs for use on the web nad much more.
http://www.gimp.org/ for Windows, Mac, Linux and others.
It is free for use everywhere including in school and at home.
Inkscape
Inkscape is a drawing program similar to Corel Draw, or Adobe Illustrator. You can use it to draw diagrams, cartoons, flowcharts etc. The atom logo on the home page of this site was drawn with inkscape.
http://www.inkscape.org/ for Windows, Mac, Linux and others.
It is free for use everywhere including in school and at home.
Tuxpaint
A painting program for kids. Very popular with the children at my school. It's easy and intuative to use for children as young as 3 or 4 but still fun for children who are much older ( I enjoy playing with myself sometimes, but I am a big kid at heart.)
http://www.newbreedsoftware.com/tuxpaint/ for Windows, Mac X, Linux and others.
It is free for use everywhere including in school and at home.
Office software
Open Office
This is a complete office suite similar in functionality to Microsoft Office. It includes a wordprocessor, spreadsheet, presentation program and database. It can opem microsoft documents and can save in microsoft formats (although its default setting is to save in in the open document format which is likely to become the new standard.)
http://www.openoffice.org/ for Windows, Mac X, Linux and others.
It is free for use everywhere including in school and at home.
Scribus
This is a desktop publishing program similar to Microsoft Publisher.
http://www.scribus.net/ for Windows, Mac X, Linux and others.
It is free for use everywhere including in school and at home.
Security software
AVG Antivirus free edition
A really good antivirus program. It can only be used on home computers, (i.e. not in schools) it cannot be installed on servers.
http://free.grisoft.com/doc/2/lng/us/tpl/v5 for Windows and Linux
Free for home use only.
Fprot Antivirus free edition
Another comercial antivirus program that is free for home use only. There is no free version for windows but you can try using the MSDOS version instead.
http://www.f-prot.com/products/home_use/ for MSDOS, Linux, BSD and Solaris.
Free for home use only.
Zone Alarm
A firewall program to prevent unauthorised access to your computer by hackers or snoopers.
Free for home use only.