We use our enterprise class development tool to build web based applications. We use the same to build facebook apps also. We've already published 3 apps in facebook. Please have a look at those apps,

http://apps.facebook.com/zcmylist
http://apps.facebook.com/junksistreasure
http://apps.facebook.com/harry-potter

and we're working on some of the apps that'll be rolled out in a week or so. We can do things faster using our tool. That is the advantage that we leverage with our customers. For more details pleas visit our site, www.zerocode.com. We do apps only with zeroCode. If interested let me know how do we move about it.