Google Voice is the perfect tool to screen your phone calls. You can set Google Voice up so it only rings your phone if people in your “My Contacts” list call you, and all other calls go directly to voice mail.
This is how do you set up a white list for Google Voice:
1. Log onto voice.google.com from your computer
2. Go to “Settings > Phones” and UNCHECK the boxes for “Forwards calls to:”
3. Go to “Settings > Groups & Circles > Callers > All Contacts” and CHECK the appropriate boxes for “When people in this group call you… Ring my:”
and that is it!
You can also set up separate rules for the various groups in your My Contacts. For example, calls from co-workers be directed to only ring your office phone, and calls from friends and family ring your mobile and home phones.
Check out this article at MacLife with 14 Great Tips and Tricks for Utilizing Google Voice for some really good lifehacking ideas to use with your Google Voice number.