[jQuery] Toggle Fade

[Dave Maharaj :: WidePixels.com]

I am trying to build a simple little effect when a user checks / un-checks a
checkbox a specific div will fade in or out depending on the check state. I
found lots of examples using toggle but I do not want to completely hide the
div, only fade it to 50% or back to 100%
 
Ideas anyone?
 
Thanks
 
Dave