Sky has launched its extended catch up TV service today, with the introduction of both the ITV Player and Demand 5 streaming portals to its Sky+ On Demand section (formerly Sky Anytime). \u00a0BBC iPlayer and 4oD will also be added later this autumn and in early 2013 respectively.In addition, the broadcaster and TV technology firm has announced a new Sky+HD box with 2TB of storage space which, Sky claims, equates to three times the amount of storage for HD content than Virgin Media's TiVo box. The new box will be capable of storing up to 350 hours of high-definition recordings.What's more, its pricing structure will be identical to the existing 1TB box. At present, that's \u00a349 for the box for existing Sky subscribers taking their first HD package or existing Sky+HD customers adding Multiroom. Other Sky+HD subscribers can get the new box for \u00a3149 for the first, \u00a3249 for subsequent boxes.New customers can get the Sky+HD 2TB box for \u00a349 when joining, with further boxes costing \u00a3249 each. Standard set-up costs also apply, which currently stand at \u00a330 for new customers, \u00a360 for existing ones.Sky has also released its Sky+ app, which offers a community based second-screen experience to subscribers. Powered by Zeebox, the app provides a live Twitter feed on programming, so you can chat about the shows you're watching. Plus, it gives a full EPG and remote control access.The Sky+ app for iPad is now available on the App Store. It also works on iPhone too.