Where can I download a free website editor so I can edit my own website?
I'm with Jack - I usually use a text editor, but if you want a WYSIWYG app that has most everything you need, I would definitely recommend Kompozer, which I previously reviewed:
Of course, there are tons. I used to be a huge fan of the free app CoffeeCup - their free HTML editor is what put them on the map in the early days:
It's still a free editor to be reckoned with.
Any text editor can be used to edit your website files. Although I've never used it as I use MS Expression and Visual studio, Notepad++ is good http://notepad-plus-plus.org/