The satellite network that GPS depends on is beginning to break down. They're old, after all, and the US Air Force simply hasn't been investing capital in this system for a while now. They won't be breaking down all at once, and there's enough discussion within the government to fix this problem that likely something is going to be done about it.
Other countries are dreaming up GPS systems of their own, everyone from India to the EU. This will provide for greater options and flexibility, as the proliferation of GPS will bring about competition which will in turn bring about better performance. But by the same token, many people falsely believe that each GPS system put into place will be compatible, allowing for superb accuracy.