The other night I downloaded a podcast directly from my iPod Touch. Now, that podcast does not sync to iTunes and seemingly doesn't exist and I cannot delete it from my Touch. I have tried everything I can think of to no avail. Any suggestions?
I found this post from ipodtouchfan.com
HERE'S HOW. on your ipod, go do the podcast you want to delete. instead of selecting it, quickly swipe your finger across to the left or to the right. a delete button will appear. delete.
The original thread: how to remove podcast from touch
Good Luck for you!