Two of the “Js” in the next-generation voice-over-IP market — JaJah and Jangl — said this week that they are partnering to combine the strengths of their complementary VoIP services.

JaJah’s strength is its telephony network and back-office capabilities, which today can terminate low-cost VoIP calls in more than 120 countries. (Jangl, by comparison, reaches just 32 countries today.) Jangl, on the other hand, has focused on getting its click-to-call widget embedded in Web sites, claiming access to more than 40 million users via partnerships with Match.com and other sites.

"This is one of the first major collaborations we've seen in the 'voice 2.0' market and, to the extent that both companies execute well, this could have some very interesting ramifications for others in this space as well,” said Rebecca Swensen, a VoIP services analyst for IDC, in a statement.

The partnered companies also will pursue an intriguing new market: ad-powered VoIP calling. Earlier this month, JaJah announced plans to work with ad network Oridian to provide a 10-second commercial in exchange for calling credits. Combining that network ad-insertion capability with Jangl’s profile-driven call widgets would give Web users free calls while providing marketers with more targeted advertising opportunities driven by social network user profiles.

The agreement stops short of a merger, but the two companies didn’t rule out such a step in the future.

Jangl said it would have more distribution partners to announce soon, further broadening its reach. It is also building widgets to Google’s new OpenSocial specifications, which will allow it to add VoIP buttons to a wider array of sites.

Adding VoIP calling to social networks has been a growing trend of late, with competitors such as Chatterbox, Jaxtr, Skype and WalkieTalkie bringing voice capabilities to Web sites.