reusing a phone(LG) bluetooth component in arduino
The difficulty with reusing the Bluetooth from the phone requires a little bit of background knowledge of what your options are for Bluetooth currently. The way most people implement bluetooth for hobbiest projects is to buy a module that provides you with a UART interface. They make it very easy to just pass data to it and have it pass you data back. These modules also incorporate a bluetooth stack that enables a serial tunnel to be created to the other device.

These modules are very expensive ($20-$30ish) and are not practical for a large manufacture to use. Instead they will usually implement the bluetooth stack themselves and will even go to the extent of making their own antenna (probably a PCB antenna). This makes it very difficult to just reuse in your own project.

Now there is a small chance that you could easily reuse it, but I do not know how and would bet there is not a way.

Here are some references if you want to learn more:

Low Cost Bluetooth

Bluetooth profiles - What is the hardware difference?

Or just look at the bluetooth tag.