how to make calls from my cell number, while using my laptop as the "headset"?
VoiceMac makes calls and SMSes via Google Voice. You can choose one of a GV number - which you keep, so your friends &amp; family can recognize it - or you can port your existing phone number into GV. The incoming caller ID will show your GV number (but no name).

Another option is to use Skype and validate your cell# as your Skype caller ID.