RIM just released v1.5 of their Payment Service SDK which is an update to the original that launched in January. This SDK allows devs to perform in app purchases through App World. This new v1.5 allows for auto renewing subscriptions for apps and in application digital goods. In other words think of subscribing to the New York Times through their app. RIM claims the API is similar though it adds the ability to check for the status of a subscription and the ability to cancel subscriptions.
BlackBerry Payment Service manages the subscription renewals automatically and sends out renewal reminders and receipts to users. The only catch is that users need the latest App World 3.0 to work. Subscriptions are offered with 7-day or 30-day renewal periods. There is also the ability to discount the initial trial subscription. This is what BBM Music is using for subscriptions. Devs can read more in the documentation here and download the SDK or more on the DevBlog.