Check out Astronomy Binoculars at BinocularChoice.com, some excellent viewing can be had given a good dark sky but even city dwellers can enjoy some great lunar views. Because it's dark when you're viewing, you'll get best results from a binocular that captures plenty of light so big lenses from 50x upwards tend to be most popular choice for the more serious sky gazers.
There is so much you can achieve with binoculars for astronomy use. Compared to telescopes they are inexpensive, very portable, have no setting up time unless you’re using some form of support. They allow excellent moon views, planetary views, star fields, comets and even deep sky objects. With views that are right-way-up they make navigation easy for beginners too. Remember that Galileo had no more power than today’s binoculars when he observed Jupiter and its moons back in the early 1600’s!
So then what are the basics when looking for binoculars that are suitable for astronomy? Amongst other things to think about planning on 40 to 50mm aperture is advisable as you want to capture as much light as possible and you’ll probably need at least 8 times magnification. Higher magnification power will make it harder to get a good image due to the handshake effect unless you are using a tripod or some other form of support. Many of the ‘giant’ binoculars are great for astronomy but they definitely need support due to their weight.
If you’re young you can make use of larger exit pupils but by the time you’ve hit your forties your pupils will not dilate past about 5mm so don’t get too immersed in that particular specification unless you are buying for a young person. You can estimate the exit pupil of a binocular by dividing the aperture in mm by the magnification (so an 8x 40 binocular has an exit pupil of 5mm).