It's the same as with non-JB'n devices, with the following enhancements:
- JB video player apps (XBMC and RushPlayer+) are able to access the entire file system - also videos in any AppStore app's Documents directory
- you can easily and quickly move videos between the Documents directories of any AppStore app. (Read the iFile-specific sections at
http://www.iphonelife.com/blog/87/combined-article-update-ios-511-ipad-32-cydia-compatibility-list for more detailed info.)