Google is now using speech recognition to make the spoken content of political videos searchable, from the Google blog:

Today [July 14, 2008], the Google speech team (part of Google Research) is launching the Google Elections Video Search gadget [view as a standalone page], our modest contribution to the electoral process. With the help of our speech recognition technologies, videos from YouTube's Politicians channels are automatically transcribed from speech to text and indexed. Using the gadget you can search not only the titles and descriptions of the videos, but also their spoken content. Additionally, since speech recognition tells us exactly when words are spoken in the video, you can jump right to the most relevant parts of the videos you find.

You basically enter your search term, and the search results section gives you a list of videos to select from (most recent first) with number of mentions of the search term.  You then select a video and the service highlights approximately where in the video your search term occurred. 

This is similar to other services such as:

• Blinkx - video search; from their site:
  
  • blinkx listens to the sound track using speech-to-text technology, looks at the images on screen using advanced video analytics, and reads other information embedded into the file by using media-analysis plug-ins to extract, for example, closed captioning.
• EveryZing - uses speech-to-text technology to make audio and video content more discoverable by search engines
• Podscope - search engine that can find podcasts according to the words spoken during them (powered by TVEyes -  makes radio & TV searchable by keyword, phrase or topic)