You can only sync to one iTunes library/computer. However, yu can manually manage music and videos among different computers/libraries.
Go to iTunes>Help>iTunes Help>Sync your iPod....>Sync You Device>Set up Syncing>Sync your device manually and follow the instructions.
it worked.... but 1st I had to make sure the movie was already imported into itunes, and not only sitting on the desktop.... (it would not work that way) I simply selected the movies folder at left of itunes window, then made sure I also slelected the ipod or ipad on the left of itunes window, and then dragged any videos from "movies" folder ONTO the movies folder of the ipod/ipad...worked like a charm..
Manual upload...without the need to SYNC the ipod!
Thank you guys!