Questions about iPhone4 calling over WiFi using Talkatone and Googlevoice..

Hello all. I have some simple questions.

I have an iPhone4 with 4.2.1 iOS. I set up Google Voice and Talkatone today.
I have made some outgoing calls ok over WiFi but the voice quality in staticy.

Here are my questions:

1. Is there another VoiP solution for making/receiving calls that is free and
uses my google number but has better voice quality that Talkatone?

2. What do I need to do to allow people to call my google number and have
it ring my phone (connected via WiFi) using Talkatone? (I took my AT&T
Simm card out) I'm kind of confused on how the whole incoming calls part
works.

Thanks for the help..

Ok I figured out my problem with incoming calls. I was still logged into
google on my computer so the calls went to my google mail.. Doh...

I still would like to know if there is a better VioP solution as Talkatone
breaks up a bit during conversations..