All very interesting suggestions. Though, sadly none of them actually work. Neither by software nor by hardware solutions.
Despite following these [and other seemingly logical suggestions elsewhere on the web] for getting non-ipad2-created-video-clips onto the ipad2, I have yet to been able to get any of my imported videos to be accepted by iMovie on the ipad2.
Yes, they will appear in either the 'videos' category or 'photos/camera roll' category [depending on how I got them on the ipad2].
And yes, once there, they will even play just fine [both video and audio] when played on the ipad2, so long as they meet the published standards for ipad2 video formats.
But to the point in question, no, iMovie does >NOT< see any of them on the ipad2. Period.
If I 'shoot' a video with the ipad2, then it works fine. Then [and so far, ONLY then] I can bring the video into iMovie. But so far, no video put on the ipad2 via any other import mechanism.
[I really do wish that people 'answering' questions actually tried their 'solution' before posting it -- or at least, prefaced their 'solution' with something like 'the following should work', or 'the following works on my mac', or 'the following might work, but I don't have the equivalent hardware to try it on'....]
The web -- you get what you pay for...