Your lens kit, or any other lens which start at 18 or 24mm, is usually good enough.
What do you mean by "far shots" of scenery?
In scenery, you want to take the 3D aspect of the subject. For example you want to take picture of a forest. There are some objects there, for example the trees, the grass, the sunrays fall between the branches, etc. To picture those objects, you need a wide angle lens which shows the relative position between objects. You will be able to see that, for example, in between the trees there are grass, the tree's root protruding from the ground, the falling sunrays between the branches, etc.
If you mean that you want to capture far subjects, you would need a telephoto lens. But beware that when a telephoto lens brings a subject closer, it is also flatenned the subject's 3D appearance. Thus if you take a photo of a forest from afar using a telephoto lens, you will see the trees, of course. But you will loose the details regarding the distance between your objects and your photo will look flat.
the kits lens for D5000 : 18-55mm is good enough for wide angle pics of scenery ..those UWA (ultra wide angle) lens like 12-24mm will cost around 1k..may be overbudget if you are just starting out in this hobby
Wide angle is what u are asking abt. BUT...your kit lens is also able to take some form of wide angle. play around with it first.
wide angles aren't cheap. probably going to cost abt the price of ur camera itself. for a good one that is.