Search Google for online anime and you’ll find 2,410,000 results. Watching episodes online have become a boom in the last two years, mostly thanks to the introduction to YouTube and its derivatives. Anyone with a decent Internet connection can upload a whole episode in under an hour, and with so many people uploading episodes, there’s such a lucrative market for websites to “index” these videos. The first site to do it (to my knowledge), was Keiichi Anime Forever, which is, ahem [bragging]my site[/bragging]. Os2 Anime began at the beginning of January 2006, and it became the largest (and only) index of episodes, totaling a few hundred series within two months. The idea took off, and there were a ton of copycat sites (it is an honor to be copied!) like PeekVid and Galbadia Hotel.
If you want to find anime episodes, or just episodes of any kind, try alluc.org and tv-links.co.uk. If absolutely no moral barriers cross your mind, you can check out movies at movieforumz.com.