Going by some media reports, including a Sunday report in the financial news website TheMarker, O2 – the mobile phone division of Telefonica – will acquire the Israeli voice over IP (VoIP) startup Jajah this week.

TheMarker, which last month reported that O2 was bidding against Microsoft and Cisco, has confirmed O2’s proposed $200 million takeover of Jajah – the VoIP firm that enables users to make overseas phone calls through the Internet. Jajah’s Internet voice calls technology is used by a number of companies including biggies like Microsoft and Yahoo.

Founded in 2005, Jajah provides the users the cheapest possible option for making long distance calls, sans the requirement of any software installation, and even without any headphones or microphones. The international calls via Jajah’s VoIP service cost less because it connects the calls directly to the overseas landlines or mobile phones through its website.

At present, Jajah boasts a nearly 15 million subscriber base, with calls currently allowed in as many as 125 countries.

Thus far, ever since its origin, Jajah has managed to raised $35 million in funding from Intel Capital, Deutsche Telekom AG, Sequoia and a few other venture capital firms.