I’ve just discovered the website 小説家になろう (Shousetsuka ni narou, or “Let’s Become a Novelist”) at http://syosetu.com/.
As explained at Wikipedia, this is a site where (usually new/aspiring) writers publish novels or light novels, which all can enjoy for free. Often the popular ones get picked up by publishers and printed as books, or adapted into manga or anime.
I discovered this because of a Crunchyroll ad for the “Knight’s & Magic” anime, which led me to the manga, which led me to the light novel available here. Ain’t Japanese culture great?
Currently, actually reading a novel is still a bit too much of a slog for me. But I’m working my way pretty happily through the Knight’s & Magic manga, and maybe by the time I finish that, I’ll be ready for the novel.
Web-based novels are pretty ideal, since you can use things like Rikaichan, or even on a phone, copy & paste to look words up as needed. So I think this will be a really useful resource for more advanced Japanese learners.