Is the iTunes sync between a pc and an iPad a two way sync? Also I recently downloaded a podcast from iTunes on to my iPad but I do not seem to late it. Where does it get stored by default?

Depends on what you are syncing.

If you have it set up right, then iTunes, App Store, and iBooks will sync back to the PC in iTunes. Most other media won't.

Audio podcasts are store din the Music app (iPod app for pre iOS 5). Video podcasts should be in the Video app.