Want to test out the latest APIs and new products from Facebook before they’re rolled out to the public? If you run a YCombinator-funded startup, you’ll be able to do exactly this. Yesterday evening Facebook hosted a number of YCombinator participants to discuss how they can make their applications more social through integration with Facebook. The company also published a blog post about a new partnership with Y Combinator.

Most significant is that the company will “provide product, technical and design resources to support new Y Combinator companies interested in working with [Facebook] to build deeply social products”. The company also told the attendees of yesterday’s afternoon event that Facebook is working on improving the mobile login process to avoid having to enter passwords.

Not disclosed was whether or not Facebook is working on a more robust mobile operating system for developers to build applications on. While Facebook has a robust Platform API for developers to integrate their applications with in order to “make them more social”, Facebook is clearly threatened by larger companies like Apple and Google who could soon launch more robust micro-transaction platforms as well as social services.

For the time being, developers who work at Y Combinator companies will have access to the latest APIs, which at least a great benefit. Given that Facebook has put their FB Fund on hold indefinitely, this new partnership provides an even greater reason to apply to become a Y Combinator-funded company.