Everybody’s doing it and so are UpNext and HeyCosmo. Both startups announced yesterday at Web2NewYork they are working on Facebook apps.

David Im of shared multimedia environment HeyCosmo couldn’t reveal much more than that he’s working on it. David is the technical man in Arsenal Interactive, the company he founded with his brother James in Mountain View, California - the brothers seem to spend a lot of time in New York these days.

UpNext’s co-founder Danny Moon and chief architect Raj Advani actually demonstrated their Facebook app that will be unleashed upon the public in a couple of weeks. It looked like just the thing UpNext needs to build their user base and stay ahead of the Googles and Yahoos.