People often ask me what Microsoft's doing with text-to-speech voice development. If you're interested in this, you may want to look at the "Mulan" project from the speech team at Microsoft Research Asia.
I've been listening to various podcasts for months now. They're a great idea, and once I found some good quality 'casts I was interested in they became a wonderful way for me to learn stuff while my eyes and hands are busy doing other things (driving, working around the house, etc). (Incidentally, I use Doppler, because I find it does a good job of converting MP3s to the .m4b format for my iPod).
So, on the topics of podcasting and TTS, it's nice to see people experimenting with using speech synthesis to convert RSS text feeds into MP3 files. I've played with Feedspeaker and I'll probably try Autocast sometime soon. I can't help feeling there's a lot of potential here.