Not much detail blankey. lol I have no experience with the playlist b/c apparently it doesn't work on the mac anyway. But if you saved your playlists I presume you can open them again if you can remember where you saved your playlists. I wasn't even aware you could utilise those for iPod. To my knowledge you can only import iTunes playlists to iPod. And there's no remove playlist command on iTunes that I can find unless you Cleared it via the Edit menu. See:
http://www.apple.com/support/itunes/...ial/index.html
I'd like to know if you can upld to your iPod by other means.