Currently, YouTube supports subtitles on videos only when they're played using their Flash player. That means that you can't see them on iOS devices, either viewing them embedded in a web page or using the YouTube app. But looking behind the scenes, it looks like YouTube does subtitles by transferring a separate XML with text and timecodes to the Flash video player. Thus, I figure it should be possible to hack together a page and script which displays the video with HTML 5 using the standard YouTube API, but also nabs that subtitle file off the server behind the scenes and parses it, then overlays the text over the video as it plays, thus making subtitled videos on iOS devices (and PCs where installing Flash is not possible/desired) possible. I think it would be a fun weekend project, but before I get started, I want to know if anyone out there has heard of someone out there already working on this, to avoid duplication of effort.