Google announced Number Porting for Google Voice today, which means you’ll be able to use Google Voice with your existing phone number. News came out last week that the company was testing this, but they have already moved beyond the testing stage and are offering it as an option. 

There are some caveats you should know, however. 

As previously reported, Google requires users to pay $20 via Google Checkout, then verify their phones. Google also tell users that their mobile phone service plan will be terminated when they port their number to Google Voice, which could result in an early termination fee from users’ existing carriers. 

Users have to setup a new mobile phone service plan with their existing carriers (or a new carrier) and request a new number. That number will have to be added to your Google Voice account as a forwarding phone.  More in the help center.

The feature is currently only available for existing Google Voice users, and will become available to new users within the next few weeks, the company says. It’s also only available in the U.S. for now. 

In other Google Voice news, Google has partnered with Project CARE for a second year to provide Google Voice accounts to homeless veterans, sot hat they have phone numbers they can use on job applications and resumes. They’ve provided 500 accounts.