Mark Jacobstein joined iSkoot as the company's new CEO, a position he took, in part, because iSkoot offers the only carrier-friendly mobile VoIP solution "in the world."

Bringing VoIP to the mobile world using the data channel, as others have done, doesn't work very well and ends up cannibalizing operators' voice revenue. What iSkoot can deliver is a solution that works well using the voice channel and "operators love it" because they can capture traffic they otherwise would miss, he says.

"The killer application for mobile has and always will be voice," he says. With presence and availability in the mix, people know whether a friend is online and therefore will call them. If they are unaware of whether their friend is online, they won't call them and the operator loses out on that potential revenue. And if they don't have a Skype solution on mobile, they'll wait until they get home to talk to someone via the PC, which, as Jacobstein notes, is an entirely unnatural way to try to talk with someone, yet people are willing to do so to save money.

In 1994, Jacobstein co-founded Small World Sports, the first networked fantasy sports game. He also was the founding president of mobile game publisher Digital Chocolate and more recently, he served as executive vice president at loopt.

While at loopt, Jacobstein would often talk about how common it is for people to ask "Where are you?" when calling someone on their mobile phone. With iSkoot, the question the solution addresses is "Are you free and can you talk?"

Alternative VoIP solution providers such as Rebtel and Jajah are indirect competitors, sharing the same cheap international long-distance value proposition, but those entities don't work with the operators. iSkoot is collaborating with Skype and U.K. mobile operator 3 on the launch of the 3 Skypephone, the first mass-market Skype-enabled mobile handset. Discussions are under way with U.S. operators.

Jacob Guedalia, iSkoot's founder and former CEO, will continue with the company as president and COO and keep his position as chairman of iSkoot's board.