the cellphone novel has taken off as a new storytelling genre in Japan. The stories are lauded as a way to keep kids reading and at the same time criticized as piles of incomplete sentences built with simplistic vocabulary.
...which means they're perfect for students of Japanese!
If you're at an intermediate level of Japanese, the cellphone novel is a easy way to bring yourself a few tiny screenfuls of Japanese text a day written in a way that is either within your reach or very accessible through tools like Rikaichan. The stories are easy to comprehend yet engaging, like little cans of condensed human emotion, and the size of each work and each page makes them feel manageable. They're available free online on cellphone based sites, but are also often accessible by PC. And as mentioned in the article above, popular ones even make it to paperback presses in Japan.
Although they aren't very scholarly, they are a step towards understanding a Japanese that street-smart textbooks can only hilariously fail to portray. That is, cellphone novels are written in the way younger generations talk to each other in texts, while chatting, or in casual personal conversation. This doesn't mean you need to need to add what you learn here to your daily vocabulary (in fact, don't: You'll probably sound something like the cast of Tokyo Drift.) I'm just saying that no matter how immaculate your teineigo is, it's only one facet of a much larger whole.
So if you haven't, consider peppering some cellphone novels in among your study of Japanese.
A great comprehensive site for them is ケータイ小説野いちご, located at http://no-ichigo.jp/
The site is pretty overpowering in its compact pinkness, so if you need a more concrete location to start, try these specific works: 甘めな年上彼氏 is a fairly recent composition that made it to press; the author, going by the pen name 秋雨, is publishing a sequel in installments as well. My own introduction to cellphone novels was 私の腐った人生, the story of a girl who spiraled into the world of Japanese soaplands as a result of her first high school crush.