If you watch or listen to a lot of podcasts on your iPhone, you're probably well aware of the stupid limitations put on direct downloading podcasts to your phone, with Apple instead pushing you to download through iTunes and sync regularly. There's a better way, and it's called Podcatcher. A $1.19 app, Podcatcher lets you dictate how, where and when you get your favourite podcasts. It's a bit of a hassle to set up - you need to manually enter the feed of your podcast rather than browsing an iTunes-like directory, and on occasion it won't actually register the feed you've entered. On the upside, you can input multiple feeds with an OPML fileBut once you've got a few feeds in there, Podcatcher starts to take control of your podcasts for you.
Using push notifications, the app will let you know if there are any new episodes of your podcasts to download, while you can set up the app to automatically download episodes of certain podcasts, no matter whether you're connected via wifi or 3G. It also lets you dictate how many episodes of each show you want to keep on your device.
It's not quite perfect, there are a few bugs that need ironing out (like the app crashing), but in terms of managing your podcasts on the device you're likely to enjoy them on most, this is far better than iTunes.