For those of you that aren't familiar with the concept, the aura is the proposed etheric energy field that surrounds the human body (as well as animals and inanimate objects). While there are methods for training yourself to view the aura with the naked eye (or at least using the faculty of vision to interpret the sensing of the aura), there exist technological methods that claim to be able to show you your aura or the aura of others.
You may be familiar with aura photographs that are sometimes sold at psychic fairs. My understanding is that these machines actually determine your skin's electrical conductivity through the apparatus you place your hand(s) on, and then this data is converted into colors which are them superimposed on your photograph. While this may give some information about your energy field, I don't feel that it shows your true aura. It is instead an interpretation of what your aura may look like based on a physical property that may or may not have anything to do with your etheric energy field.
The second, and perhaps the most popular, "aura-viewing" technology is Kirlian photography. An object (usually living) is placed on an electrically charged plate in complete darkness and then a snapshot is taken. What shows up on the photograph appears to be similar to the concept of the aura; it is light surrounding the physical form and even extending to complete an incomplete physical form. However, what is captured in a Kirlian photograph is believed to be the coronal discharge of whatever is being photographed. While interesting, I don't think that these can be said to be true aura images any more than "aura photographs" can.
The third technological method that I'm aware of (and apparently the oldest) is a Kilner Screen. I had not heard of this device until a few days ago and I have to say that I'm rather excited about it as it seems to be the simplest and most low-tech of all the devices said to be capable of viewing the aura. It also seems to be the only one capable of viewing what I consider to be the "true aura," (the etheric energy emanating from the body) rather than some spark brought about by electrical charge or some colored photo made by a computer from skin readings.
What is a Kilner Screen then? It consists of two pieces of glass with a particular dye encapsulated in the middle. One looks through this screen in order to train the eye to see the aura. After training, the screen is no longer necessary. The only drawbacks of this device seem to be the rarity and hazard of the dyes used in making the screens.
I have been able to see auras (when I want to) for a few years now and I don't find it to be particularly interesting. Some people do though, so for those that are having trouble acquiring the skill with naked-eye methods there is the option of making or procuring a Kilner Screen (or a similar device that doesn't use the nasty chemicals). To this end, I provide the links below.
The Wikipedia article on Walter Kilner, the inventor of the screens.
A much more in-depth look at Kilner's methods and the aura itself. (I agree with most of the observations made about the aura as they largely coincide with my own observations.)