here's a couple of websites I've found and used

the first is www.alienryderflex.com/rotoscope/ and involves a fair bit of work as you have to draw each frame of the sabre.

the second is better as it's done in adobe after effects and so you use keyframes. as such you don't have to rotoscope each frame, after effects can do som of the inbetweening. still a long process though.

out of the two I prefer the second as its a bit more realistic.

this is the second http://ryanw.michaelfrisk.com/ryan-w/tutorials.html .
Incidentally the guy who does the second tutorial has now been employed by Lucasarts as an effects associate.

there are more out there if you just google for them but these are the best two I've found and used so far.