After the acquisition of Gizmo5 last year by Google it seems to be working on integrating it with Google voice to compete directly with Skype. Gizmo5 is a Voip service that competed with skype making P2p calls possible over normal landlines and mobile phones.
Techcrunch reports that Google is testing its intergration of google voice with Gizmo5 so it can use its voice phone number over desktop and competing with skype directly.
Sources have confirmed that Google has a desktop application to make and recieve calls and is being tested internally. Google is working towards letting users be able to make and recieve calls by combining services from Gizmo5 and Google voice together.
The new application might be out in a month or sooner. Testing it internally, Google projects a release date no later than June.