Answer:
Yes, indeed there are. There is a superb, ultra-modern Visitor's Centre on the summit, which is accessed by the narrow-gauge steam railway. The Centre comprises a restaurant, rest rooms, toilets, an educational exhibition room for visitors which explains all about the geology and natural history of the area, and a viewing gallery from which to take in the scenery.
There has been some discussion in the Welsh Assembly as to whether to extend the Visitor's Centre to include a small hotel and hostel for walkers, though this doesn't exist there at the present time.