Thanks a lot, PaulS and gerg for your answers.
Well, my application is very simple. The first thing i need to do is send an audio signal to a bluetooth headset, that's all. I thougth use a Bluegiga module for this, but it would need to do the PCB with all the stuff. Someone told me work with arduino is easier. So I looked and I found a problem...
My problem is that the information about arduino BT and WT11 are contradict:
*Arduino BT info: "The Arduino BT is a microcontroller board originally was based on the ATmega168, but now is supplied with the 328. (datasheet) and the Bluegiga WT11 bluetooth module (details and datasheet [pdf]). It supports wireless serial communication over bluetooth (but is not compatible with Bluetooth headsets or other audio devices)."
*Bluegiga's Answer about if link WT11 with headsets is possible: "Yes it is possible as we support the HFP profile in our firmware."
So, for understand this, the problem is not the module used, the problem is that the arduino capabilities aren't sufficient, is that so?
Thanks again for your help, greetings from Chile