Kindle question

For those of you who have a Kindle, how easy is it to put, say, fanfic on it? I am imagining that I could c&p fics into txt files or even download them as pdfs, and then put them on a Kindle to read wherever. That would be amazingly awesome. :-)

I'm having a little trouble finding an answer via google, oddly. Can anyone advise?

ETA: My flist knows all! ♥