Worth a look. (Excellent software if you're seeking that sort of stuff):
http://www.freeserifsoftware.com/
The most well-known free software site:
http://download.cnet.com/windows/
(Carry out an initial search for the type of software you require, then use the filters - which will appear down the left of the results pages - to select 'Free' and the relevant operating system. Always read the reviews carefully).
An alternative sight to Download.com:
http://www.tucows.com
(Some good software but harder to find it).
Chris