I’ve been looking around a bit about chinese-english online dictionaries and www.nciku.com seems like one of the best. It seems to have some trouble doing some searches cause their servers are overloaded, but you can search with english or chinese text, pinyin, and even drawing in characters. The definitions come out pretty thoroughly and include audio and stroke order animations and a rudimentary character composition chart (which is the weakest feature of the bunch). Throw in easy to manage vocab lists and a lot of sample conversations and stuff and it’s one hell of a package.
Plus it’s all for free at the moment. The other site of note is skritter but it’s a pay site and not as much a dictionary. In the end, I’ll most likely default to flashcards on quarter size index cards, but it’s amazing what online stuff is coming out now….and once phone and touchscreen apps become mature it will be a sea change in how this stuff is taught.