Do a Google search with the term FREEWARE, that will get you the software, now good is a relative term.

www.freewarehome.com is a site to check out for some good freeware but as always every where you go you have to kiss a lot of frogs to find a prince.

Specific software that is good and free

Office stuff - OPENOFFICE.org

Graphic editing - GIMP

There is a lot of good stuff out there, but a lot of what the web can recommend is determined by your needs, the more specific your requirements are the more specific the replies are going to be.

An example of that would be http://hubpages.com/hub/Free_Photo_Editing_Software_