Not sure where podcasts are, but my best guess would be in the following path:
/var/root/Media/iTunes_Control/Music
That's where videos and music is located. You'll need to learn how to SSH into your ipod and use it in order to get there though. To start you off, download openSSH on your ipod through cydia then download WinSCP onto your computer. Link is here: http://winscp.net/eng/download.php
When you enter the Music folder, there will be multiple folders usually named 01, 02, 03, etc...those folders contain every piece of media on your ipod including movies, tv shows, songs, and possibly your podcasts. Copy those to your computer using winSCP (just highlight all the folders and drag them to your my documents folder or something). Then you can re add them all to itunes.
Some songs, depending if you've bought them from itunes or not, won't be named. They'll show up as "DG824" when added to itunes. YOu'll have to manually name them again.