Yes, you can uncheck Play Audio When Scrubbing in Preferences. I sort of toggle back and forth, depending on what I need.
There is also a kb shortcut to toggle audio while scrubbing on and off, at least in CS6.
As for the second question -- Shift+J/L. This is also in CS5.5. I do not remember if it is in earlier versions.
Is there a way to turn off the audio scrubbing sound head as you advance the Scrubber through the Timeline?
Which keys are used to play footage forward and backwards in slow motion?
Thanks for the keyboard shortcuts. I had not found those, but then had not gone looking.