The four loop expressions:

loop_out(“cycle”,0)

loop_out(“pingpong”,0)

loop_out(“offset”,0)

loop_out(“continue”)

will loop most keyframed properties

Press Command and scrub through timeline to hear audio scrubbing in After Effects

http://www.motionscript.com/design-guide/wiggle-1-dimension.html

http://www.dvpa.com/public/536.cfm