You need to put movies or videos into the iPad Media folder (/var/mobile/Media). The easiest way is to put them in there using your computer (either SSH in, after installing Open SSH - or using a program like iFunbox). Once the videos are in that folder, then you can just open VLC and it'll present you with a menu to select which video you want to play.
Hope this clarifies. Let us know how you get on.
Marilyn
P.S. And, since you talk about a jail broken iPad, I've taken the liberty of moving your post over to the Hacking section. Thanks for your understanding.