I talked to someone once about super slow-mo effect he used on a film that added frames in to smooth the motion rather than just changing the speed in FCP. I think that it was some kind of animation software. Is there any special tricks to do this same kind of thing in FCP?

There are plug-ins/programs like Boris Optical Flow, Shake, RevisionFX ?Twixtor? that will guess the in-between frames.

I don't think you can do this for free in FCP.

In the sequence settings box under video processing change it to linear and then export your slow-mo clips as quicktimes and import them back into your regular sequence. I'm not sure how slow you can actually go I've only went to 50% but it seemed to work alright.

Thanks I'll try that. As for the free part, I'd be willing to pay for a program/plug-in or anything that would work right.