By this time, you probably must have seen the video demo of Google Voice Desktop App (Gizmo5). The app is internally tested by Google, since April this year. The problem isn't about waiting until Google finishes and ships it off. But, there's a real possibility that Google will never release a Skype-like soft phone for the desktop. An online petition is poped up in its support:
"We've asked, begged, and pleaded for a desktop VoIP app. We've heard news of said app and then sadly heard news of this app possibly being dropped for your "to-do list". This petition is brought forth to show you the overwhelming demand for such an app for OS/X, Windows, and Linux PCs (and possibly an Android App). We understand your hesitation for a desktop app, but a web app would be far too complicated at this time to create. Please hear our voices. We use your services daily and stay loyal to your company," read the site.
More Info: PetitionSpot