+1 on google voice.
Just did this with our home phone. Moved it to vonage several years ago, but price and fees kept going up. We hardly used it anymore, but wanted to keep it. Had to port it to google in a two step process, because you can't port from vonage to GV. Used a $10 t-mobile prepaid SIM as an intermediate step.
You can use the
Obi gateway to connect your house phones to google. No PC needed.
The only downside is no 911 support. You have to call the local dispatch center phone number instead.