I am designing a noise monitor for our school cafeteria that will behave somewhat like a typical VU meter but without the immediate cascading up and down. If possible, values taken from an LM386 will be fed to my Arduino for establishing thresholds that will light LED's. How do I read values from the LM386? I have tried a variety of components with no success. I would appreciate advise.

 

The output of the LM386 swings from +1V to the supply voltage -1V at clipping.
If you use the output coupling capacitor then its output swings above and below 0V.
When the output of the coupling capacitor swings below 0V then it destroys the input of your micro-controller.

 

Search on "LM3914" on this site. The IC might do what you wish without the uC.

 

If you mean you need to monitor noise levels, Radio Shack used to sell a cheap but useful handheld portable SPL meter that runs on a 9V battery. I have one, they used to sell for about $30. Already calibrated in both A and C weighting and has ranges all the way up to 140 dB.