There’s no shortage of companies offering tournament-game platforms. But YooMee Games is announcing today that it is going after the market with a unique twist, focusing on casual games that can be played across web sites, social networks and mobile devices.

The company will have a tough time carving out a niche in the market. But it hopes to execute better than others on the combination of tournament play and casual games across multiple platforms. It is not going to be easy by any means, given a wide range of rivals from Virgin Gaming to Zynga.

The San Francisco startup is beginning today with the launch of a new consumer gaming portal, Players can access 25 popular casual games such as puzzle titles like Bubble Town, word games like WordStone, and classic arcade-style games such as Break It, a clone of Pong.

The site offers real cash and prizes for those who play tournaments, enter one-on-one challenges, or compete against their own high scores. Hundreds of millions of people are playing casual games once a month, and they’re spending a lot of money on virtual goods and currencies. Prita Uppal, chief executive of YooMee Games, said in an interview that most tournament game companies focus on hardcore game players. But her company is targeting the older women who play casual games. Zynga is the biggest competitor in that part of the market, given its nearly 300 million monthly active users on Facebook. But Zynga doesn’t do much in real rewards for online play.

“The other companies don’t have a pure tournament component,” she said.

YooMee Games will let players purchase virtual currency and then make wagers with it. They can earn rewards for game play in the form of Tickets, which are redeemable either for cash or a prize. It’s a lot like a typical arcade or carnival business model.

Uppal said that YooMee Games differentiates itself by adding social platforms such as Facebook, MySpace and mobile apps. Users can thus play against their real-world friends. They can access high scores, game history, currencies, and challenge their friends. The game portal has been in testing for a while, and Uppal said more than 3.5 million games have been played across the company’s network to date.

YooMee supports all mobile game platforms and versions of Adobe Flash. It can thus enable game developers to create games for new platforms and make money from them. The company currently has partnerships with 53 top game studios, including indie developers Hipsoft, Mumbo Jumbo, and Ocean Breeze Games. Web publishers can embed the YooMee game platform on their own web sites; Uppal said the result could be more engagement and traffic for those web sites. Game publisher partners include PopCap Games and Digital Chocolate.

Uppal said that the company doesn’t develop its own games; rather, it gets games from developers who want to spread their titles online. With that model, it will be tough for YooMee Games to come up with differentiated content. The company has funding from Altos Ventures and US Venture Partners. YooMee Games was founded in 2008 and has 17 employees. Rivals include Game Duell,, Worldwinner, Frosmo, and Xfire. To date, the company has raised $4.5 million.

Uppal got immersed in social gaming while getting her Harvard MBA. She says she loves the rush of playing games for real prizes and that she is a gambler at heart. So much so that she decided to start the company. She saw that casual games weren’t being monetized to their full potential, so she wanted to create a new solution to reach a wide audience.

Her company, she said, is like the house in a casino. It takes a small fee from every currency transaction. Uppal previously started a DVD gaming company focused on Bollywood trivia; that company did well in the Indian market.