iSkoot, the company that puts Skype on mobile phones, has raised $19 million in a third round of funding from Vision Opportunity Master Fund, which led the round, and existing investors Charles River Ventures, Khosla Ventures, Jesselson Capital Corporation and ZG Ventures.

The funding, which brings the company’s total investment to more than $32 million, will be used to build a mobile platform for AT&T (NYSE: T), reports Venturebeat.com. The platform is to roll out for testing next week, and will let the carrier offer a number of web services—including social networking, email, RSS feeds and eventually services like Twitter—on low-end phones. AT&T was particularly attracted to iSkoot for its ability to integrate the applications deep into the phone. Skype, for example, is so deeply embedded in the software stack that Skype contacts are integrated directly into the phone’s address book. According to Venturebeat, if iSkoot can do that with Skype, they can “theoretically” do that for “everything from Twitter to Facebook.”