Tonko Jikai Chinese-Japanese Dictionary
An easy to use simplified Chinese↔Japanese dictionary with definitions and example phrases -- for some reason it also tells you how many other searchers have pulled up the same word. It also hosts a forum for questions about Chinese. The website is only available in Japanese, but it's easy to figure out, really. On the off chance that you can't navigate it, they even have a nifty diagram on how one uses a search box right on the front page!