Previously, we’ve informed you guys that Google officially implemented Incoming Number Portability, which lets you to port your own phone number into its system. Google has just announced that all the Google Voice users can be able to get the Number Porting feature and port their existing mobile number from their handset carrier to Google Voice account, that means to move their primary phone number to Google Voice and then forward to a new number assigned by their carrier
Previously, only some noted users were given the ability to attain this feature, but now they’ve covered it to all existing GV users. Google is charging a $20 fee for number porting into Google Voice and Google has confirmed that will take approximately 24 hours to fully complete and after the process gets finished, your existed mobile service plan will be invalidated and you need to make some sense to continue making phone calls and receiving. New users will be getting this feature within the next few weeks.
To port your number into your Google Voice account, You just go to Settings in the top right corner, and then Voice settings. Now, on the phone tab next to your Google Voice number, click Change / Port. Now click on “I want to use my existing mobile number instead” and follow the on-screen instructions to port your number. There you go — you now have ***-**** as your phone number and $20 less in your wallet. Check out the video at below explaining the process of number porting.
[Source: Google Blog]