Evan Abrams with a look at making things twitch in After Effects by way of expressions. Evan has provided six different tutorials all dealing with using expressions for getting objects to twitch, jitter and shake in AE for every skill level.
So you want to make things twitch around but hate having to keyframe? Enjoy saving some sweet time with this expression tutorial series
Evan notes that if you are savvy to AE and expressions you can skip right over to part 6 of the tutorial, and if you are a first-timer, you can start at part one and continue on from there. Be sure to check out Evan on his site EvenAbrams.com for more great tutorials.