Make Your Own Free Phone Service by Combining Google Voice with Other VOIP Services.
First you must sign up for a free Google Voice number. This gives you a local number and voicemail.
Then you need to have a VOIP number for one of the many VOIP providers out there. I personally prefer to use Sipgate but there are many others. Sipgate, as do many other VOIP providers give you a free incoming only phone number that uses SIP.
You can use this number with Google Voice to make outgoing calls as well as receive calls. The VOIP provider will provide you with your SIP user id , password and settings to configure any IP phones or ATA boxes you have.
I use the Linksys PAP2T-NA ATA to create an analog telephone line to connect my home phones to VOIP service. This device allows you to use normal analog household phones with your VOIP service. Now, when you buy your ATA or IP Phones they must be unlocked (not assigned to a specified VOIP service like Vonage, etc.). I ordered one from Amazon, I have seen them on eBay as well.
Once you get your ATA or IP phone configured ( most VOIP provides have a "how to" on the config. of their service on their website) you will get a dial tone.
Now, you just setup Google Voice to ring that VOIP phone number. So now... if you want to call someone, you just click on that person from your contacts list in Google Voice and Google Voice will call your VOIP phone number configured in your ATA and also call the person you want to call and connect you...Cool. If someone wants to call you they just call your Google Voice number and Google Voice rings you VOIP number configured in your ATA.
Recently a new ATA device has become available that makes this even easier by using your Google Chat and Google Voice accounts together to make a completely seamless free phone service. Read my recent posting on this device here and let me know what you think...
There you have it... Free phone service!