100% Free Landline Calls using the default OS2008 Internet Call app (VOIP):

Installation
1. sign up for gizmo
2. sign up for grandcentral
3. setup grandcentral using your gizmo 10-digit phone no.
4. update rtcomm
5. setup an internet call account - pg. 27
* select the “sipphone.com” service
* enter your gizmo username/password

Use
Incoming Calls:
Landline calls to the grandcentral phone no. => ring the tablet as an internet call (voip)

Outgoing Calls:
Calls from the grandcentral.com address book (or inbox) => ring the tablet as an internet call (voip) => ring the landline

note: if flash player is not available, a. use grandcentral.com/mobile and b. select gizmo no. as your mobile number.

This procedure is due to the open-source projects which are part of the Internet Communications Software and many internettablettalk members

Yes, this is awesome, I just figured this out the other day.

It should be noted, though, at some point the outgoing call point may become not free.

http://www.grandcentral.com/support/showanswer/605 says:

"Will GrandCentral always be free?
Our current plan is to offer a free service with as many features as we can and later add paid features at a very affordable prices. During beta, all available features are free."

Also, from the FAQ:

"Will GrandCentral always be free?
Yes, we're excited to say that we will always offer a free version of GrandCentral, even after beta. Our free version will include unlimited inbound minutes, unlimited voicemail (up to 30 days old), and access to all of our core features. During beta, we're giving everyone unlimited access to our premium features. In exchange, all we ask is that you send us your feedback (good or bad) to beta@grandcentral.com. We'll read every comment."

However, it is Google now, and you know how long their betas generally last. So you may be able to enjoy the free outgoing calls for a long time, who knows?

-SG

To actually answer an incoming call from GrandCentral, when the call comes in go to the main menu and select Internet call->DTMF Dialing and then press "1" on the keypad to answer the call.

If there is an easier way to do this I would sure like to know.

Unique311 posted this on IRC yesterday:
http://www.youtube.com/watch?v=mhJpS5doGZM

Hmm, what's the purpose of updating rtcomm? I just tried without it and it seems to work (well it echoes but that's probably because I'm talking on my cell phone and tablet at the same time lol).

I'd love to try this. But the Grandcentral site says "GrandCentral is currently a private beta service, which means you must receive an invite from GrandCentral or a GrandCentral user to sign up."

Would someone be so kind as to invite me? My email: anonymous469@gmail.com

Thanks so much!

You can just go to the website and hit reserve a # and they'll send you an invite. But as soon as I get one I'll send you one.

Thanks Laughing Man!

Ok I think I sent you one.

In step #5 of dkwatts' instruction, how should I complete the ID after the @ sign? I tried (myusername)@gizmoproject.com, but it didn't work.