The files need to be mpeg 4 to import to iTunes or iPod. Nothing else will import. Not mpeg1 or 2, or avi, etc. H.264 is a high quality mpeg 4 format that can import into both. If you can't import a video into iTunes, then you definitely won't be able to import it into iPod!
If the files won't import, then you'll need to convert them. See both
Videos for iPod/iTunes & also these iTunes Tutorial
http://www.apple.com/support/itunes...rial/index.html
iPod Tutorial:
http://www.apple.com/support/ipod/tutorial/index.html