Asked and answered right here...
http://www.ipadforums.net/ipad-help/2703-deleting-podcasts-ipad.html
Remember...search is your friend.
Use the search button located in the toolbar at the top of every page. Of course, if you don't find the answer you're looking for, feel free to post.
Essentially it's this (thanks Stever):
- On your iPad, go to 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.
To delete a podcast from from iTunes Control-click/right-click on the podcast you no longer want and click on "delete" from the menu.
Hope that helps and enjoy!