Please do not add to this without reviewing the comments on the page above it.
The owner of this Schtuff "Space" (wiki) has an established set of pages about free software at www.arunet.co.uk/tkboyd/hh6f.htm . The wiki is not intended to simply be a "link farm" to other stuff you could just as easily find with Google, and I will remove this entry in due course... but while this page is so thinly populated, I decided to put this link in.