How do you watch videos on your iPhone? When the original iPhone launched -- 4 years ago today! -- it came with an iPod app that could play iTunes/H.264 MP4 movies and video podcasts, and a last minute YouTube app addition for online videos. Fast forward to today and iOS 5 is set to break the iPod app in two, Videos and Music just like iPod touch and iPad, YouTube can be played in Safari and embedded web views via Google's web app, and a host of other sites and services now make apps and web apps as well.
There's Netflix and Hulu, ABC and Global, and BBC and MLB, HBO and Comcast, Ustream and Air Video, and a ton of others.