Tunes - Tuneflow

Mac OS X only: Free, open-source application Vocito puts Google's one-phone-number-to-rule-them-all application GrandCentral on your desktop, integrating directly with your Address Book contacts. The most obvious way to place a call once you launch Vocito and enter your GrandCentral login is to click the new menu bar item, search for the contact you want to call, and place your call—but it's by no means the only way.

iPhone/iPod touch only: Free application GrandDialer integrates with previously mentioned GrandCentral—Google's phone-consolidation service—so you can seamlessly call contacts from your iPhone using your GrandCentral number.

Firefox only (Windows/Mac/Linux): The GrandCentral Click to Call Firefox extension calls phone numbers on web pages using your GrandCentral account with the click of your mouse. That means whenever a web page loads, the extension recognizes phone numbers on the page and turns them into clickable links.