interpolation between frames?

I've been trying to think of ways to interpolate between frames of video so
I could do smooth slow motion work with footage shot at standard speed. It
could also be useful for creating effects that people have been doing with
twixtor on the fly...mmm.
I've taken a look at the cv.jit objects which seem to offer some objects
that could be used but I'll need to learn more about them before I could
actually do anything effective with them. Ideally I'd be able to choose how
many interpolated slices went between each frame, but that's kind of a tall
order at the moment. I really need to learn more about image analysis and
synthesis.

Has anyone else done any work doing interpolation between frames of video?
I'd love to see how you've approached the issue.

Bryan