Can you use the API to add new subscriptions for users in your app?
Can you use FQL to see what subscriptions a user currently has?
No. User subscription lists are not part of the Facebook Graph API yet. As such, they also cannot be read through FQL. When they are added, they will most likely be read-only much like a user's friend list currently is. The idea is that Facebook doesn't want to allow people to make subscriptions or find and send friend requests from a third-party site. If people aren't visiting Facebook to make connections, Facebook doesn't make a profit from ads. It's just one of the ways in which they've closed off the API so that it isn't too "free" for developers to make sites that function exactly like Facebook.