Hi guys,
Thanks for your comments.
I've got now the wiichuck working of a 3.3V pin. I haven't integrate it yet to my code but I'm moving a servo with the movement of the wiichuck. Just a note for the people using the Mega... remember that SDA and SCL are on pins 20 & 21 (not 4&5) so if you follow some tutorials on the wiichuck remeber to use pins 20 and 21 instead of 4 & 5.
Regarding the BT I will contact the manufacturer then. But whatever they say I will still need a BT transceiver from the Arduino Mega, isn't it? Any recommendation on which one?