Change delay value in Arduino Sketch based on slider value in MIT App Inventor

First off, thanks for all the help in the forums. I have learned a ton in a very short amount of time, which has allowed me to build a pretty robust app. I am only hung up on one item.

I have created a slider in App Inventor which generates a value from 0 to 3500. Can anyone advise how I can get this value to change the delay value in Arduino Sketch?

EX:
Delay is set to 3500 in Arduino
If slider changes to value of 2500, then automatically change the delay in Arduino to 2500

delay(sliderValue);

assuming the value of the slider is in variable sliderValue.

I am guessing, but won't you have to use serial communications of some type between both machines?

Have you searched the Arduino forum for App Inventor? You are not the first to connect the devices.

Paul