but it seems you are talking about Google Voice.
See if this helps;
http://www.google.com.uy/support/forum/p/voice/thread?tid=7d3a5047281cc968&hl=en
If not, search through Google's own site for How to remove Google landline service.
I assume Google's own online Help articles, or their telephone Customer Help Center were not able to help you.
Mark
Having spent hours online trying to research this issue, it seems that it's an app. so I cannot totally get rid of google talk. I along with several others have complained of issues with landline phone ie ring and static problems. Having enjoyed so many other Google products I do not want to completely get rid of my e-mail and other products yet this is the only option that I have found that they offered.

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