Google is now offering automatic captions (auto-caps) in YouTube.   Video captions are generated using Google's speech recognition technology.  From the official blog post:

[...] we've combined Google's automatic speech recognition (ASR) technology with the YouTube caption system to offer automatic captions, or auto-caps for short. Auto-caps use the same voice recognition algorithms in Google Voice to automatically generate captions for video. The captions will not always be perfect (check out the video below for an amusing example), but [...] the technology will continue to improve with time.

They are also have another related feature called auto-timing that can create time stamps of words uttered in a video (if you upload the  transcriptions along with the video).  The resulting time stamp file is downloadable.  From the blog:

[...] we’re also launching automatic caption timing, or auto-timing, to make it significantly easier to create captions manually. With auto-timing, you no longer need to have special expertise to create your own captions in YouTube. All you need to do is create a simple text file with all the words in the video and we’ll use Google’s ASR technology to figure out when the words are spoken and create captions for your video. [...]

Seems like an easier way to perform forced alignment on the audio track of a YouTube video...