One thing that my HTC Inspire Android phone running CyanogenMod 7 lacks that my 5th gen iPod running Rockbox had is the ability to speed up podcasts and audiobooks so that they can be listened to in half the time. Fortunately there's an app for that. It's called xSpeedPlayer and it's a free app on the Android Market.
I use xSpeedPlayer for speeding up podcasts to 1.5X or 2X speed, depending on how fast the hosts are already talking. It's great for getting through a long podcast and absorbing the information without wasting a lot of time on the chit-chat and off-topic stuff some podcasts get into on occasion. I'm able to understand and retain information just as well at 1.5X speed as I am at normal playback for most podcasts, and some slow ones I can play at 2X speed without missing anything.
xSpeedPlayer doesn't alter the pitch of the hosts voices so they don't sound like chipmunks when you alter the playspeed. This app is exactly what I'd been looking for on Android. You can playback your mp3 podcast files faster or use the app to save the faster speed audio to a new file.
As I get used to hearing podcasts at 1.5X speed I've started to get annoyed while watching television since I can't speed that up without downloading shows to my computer and using VLC or SMplayer to speed up playback. Normal speed content seems so slow now. I hope I don't start getting annoyed when people in real life talk slowly...
I expect that overtime as I learn to listen better to higher speed audio playback I'll be able to start shifting more podcasts to 2X speed for even more time savings. So long as I'm able to understand and retain the useful information in the podcast it's worth doing. I'll have more time to play games! xSpeedPlayer can speed up podcasts all the way to 4X speed, but I think that might be too fast for most people. Cutting listening times in half is already such an improvement though.
You also have the option to playback audio at a slower speed, though I can't imagine what this would be used for. Decoding high speed burst transmissions maybe? Probably better to use Audacity on a desktop for that.
xSpeedPlayer works with downloaded mp3 or wav files, so you can't use it on streaming audio, but that's a minor gripe. Although I suppose there could be some way around that by using a podcast client that lets you output files to external audio players.
You can also apparently set xSpeedPlayer to playback multiple files in order, though I haven't yet used this functionality myself.
Anyone who listens to podcasts on an Android device should get xSpeedPlayer. You'll get used to the faster audio really quickly and if you listen to a lot of podcasts the time savings will add up. You won't want to go back to standard speed podcasts once you're used to 2X playback. This is really something that should be built into the core Android media playback framework, but until/unless that gets implemented this is your best bet for speeding up podcasts on Android.