Games have become increasingly popular across platforms — meaning that developers have to build different versions of the game for, say, Facebook and the iPhone. So, Sibblingz is a new company trying to make it easier for developers to build a single game that runs on both those platforms and the web, while offering a single social context to users.

For example, you’d be able to play a single game on all three platforms, and see the same leaderboard with all of the same friends. It uses Facebook Connect to provide friend relationships, messaging and other social features, thereby potentially helping games to grow.

The service is going into private beta today, and we haven’t gotten a close look at it yet, although you can see Facebook and web versions of a game, called Little Monsters, on the company’s web site (the iPhone demo doesn’t appear to be live yet).

Specific features that the Sibblingz framework offers include: avatar customization, 3-dimensional virtual spaces, a virtual goods plus a store to sell them out of, a “nurturing” mechanic and “monetization” (think: currency and payments). Developers choose their game design of choice, design it to integrate with Sibblingz features, and publish it across platforms using Siblingz’s servers. There’s no upfront cost, but developers share a portion of their revenue with the company.

A number of others are trying to offer similar features, with some, like Live Gamer, offering services such as virtual economy management. A range of iPhone companies offer social features for other iPhone games, including Ngmoco‘s Plus+, Scoreloop and OpenFeint. Sibblingz is trying to differentiate itself by offering a specific range of features that are easy to integrate across platforms.

Speaking of OpenFeint, it shares a common investor and chairman with Sibblingz in the form of Peter Relan — who is also an investor in and chairman of CrowdStar (which we covered in some detail yesterday). All three companies came out of his incubator, YouWeb.