I have recently come of a contract at Tricycle Developments, and one of the projects I was working on was a site called Podshifter. The concept is simple: take a podcast URL, look at the MP3 enclosures, and speed them up. The new iPhone OS likewise has a feature that will play back your normal podcasts at so-called 2× their normal speed (I think it is actually 1.5×).
The revelation here is that we can process audio much faster than we hear it. This is often why we tune people out, even when they are right in front of us. They are simply speaking too slooooooowly. [We sometimes hear tips when presenting to talk slowly. I find this to be a bad idea.]
So, for audio, check out Podshifter or upgrade your iPhone/iPod Touch if you've got one. If you have existing audio files that you'd like sped up, you might give Huffduffer a try to create Podcast with audio enclosures. Then, feed that podcast to Podshifter.
For video, things aren't as straightforward. If you're taking video podcasts on the go, you're probably out of luck. However, if you have a PC or Mac handy, VLC does a good job of speeding up videos. Just press + when your movie is playing. Each time you press it, your movie will play faster. Unfortunately, there isn't an easy way that I know of to export the faster video. If you know, do leave a comment.
