Virtual currency enabler Jambool announced today that its Social Gold virtual currency and payment system will be used in online games on the big casual games portal Miniclip.

The partnership will enable virtual goods purchases across Miniclip’s catalog of 550 games. It will also allow seamless in-game payments for Miniclip’s 57 million unique users per month. That means the players can purchase virtual goods — decorations or vehicles — without leaving the game itself.

The deal is an important win for San Francisco-based Jambool, which has a lot of traction in social networks such as Facebook. The deal should also help Miniclip better monetize its users. The Social Gold solution works with Flash, which is a kind of lingua franca for casual online games. The payment system helps remove friction from online game purchases by making them easy.

Jambool has 25 employees and was founded in 2006. Social Gold launched in October, 2008. Its rivals include PlaySpan and Live Gamer. Jambool raised $6 million from Hit Forge, Charles River Ventures, Bay Partners, and Madrona Venture Group.