For podcasting try Gpodder. There's a version you can install directly onto the tablet, or you can install it in PC (Windows or Linux) and then set it up so you can transfer it over to a mobile device (either via USB or tell it to sync to a directory and ssh it over).

As for the iTunes database. YUP! You can. It's slightly annoying to do because it requires iTunes but the reason why is Apple obsfucated the URLs. Just subscribe to whatever podcasts that are iTunes only in iTunes. Then rightclick the podcasts playlsit and tell it to output as OPML. Then import that OPML into your rss feed, media player of choice and TADA it works!

Though one thing I have noticed about the iTouch and iPhone is the lack of a widget system. Which is strange considering Apple likes to brag about how they pioneered the idea..for weather you actually have to go into the weather application (the icon won't update always with the correct weather). And likewise for SMS messages (only the number), and whatever else you would normally look at a home screen for a quick update.