The Shiva lingam can be used as an object of concentration. It can be used as a focus for your awareness. It can be used to draw you into the deeper realms of your being. It can be used as a vehicle to higher experience.
The Shiva lingam is a widely symbol in India. It is a tantric symbol, as well as being an integral part of Hinduism.
But the veneration of the lingam is not confined to India. It has been venerated throughout every part of the world, especially in by gone ages. It is a symbol which is buried in the deeper layers of your psyche. Probably you don't know this, but nevertheless it is there. It is waiting to be brought to the surface, to conscious perception, together with all the knowledge that surrounds it. If you bring the symbol up from the depths, then you will simultaneously realize the incredible reality that it represents, If you have time, concentrate on the lingam; reflect on its meaning. And if your concentration and reflection is sufficiently intense and one pointed, then you will bring a veritable jewel of knowledge to your awareness - you will bring a prize to the surface of the mind. Or if you like we can put it another way; if you submerge yourself into the mind by intense concentration on the lingam, then you will start to plummet, to explore the depths of the mind. Whichever way you look at the process, the result is the same.
Actually, we don't want to write reams of material on the meaning of the Shiva lingam, for this is something that you must realize for yourself. Furthermore, the lingam has different meanings according to the level of understanding. Thus to say one thing about the lingam, can seem to be contradicted by the meaning at another level. Therefore don't take any explanation too seriously, find out the meaning for yourself and according to your level of awareness.
The word Lingam means symbol or sign. In the tantric sect of Shaivism (followers of Shiva) the lingam is the most important symbol. It represents consciousness or Shiva. There is a beautiful song about the Shiva lingam in India. It is called 'linga sthakam'.
The picture of lingam can be used as an object of concentration. You can practice the meditative practice of trataka described in August Kriya. If you can visualize the lingam in front of your closed eyes (in the chidakasha) then this is an even better practice.
Incidentally, there is an excellent practice in Shaivism which use a small, well polished lingam and a candle. The candle is placed behind and above your left shoulder so that it shines on the Shiva lingam held in front of the face. This produces a tiny dot of light on the surface of the lingam, which can then be used as a fixed point for concentration. This is a method of trataka, but it is more refined for it is combined with ritual worship, and mantras and other refinements that heighten the effectiveness of the practice. We have not given full detail, for a specially made lingam is necessary, and they are not readily available. We have only mentioned the practice from the point of view of interest. It is an excellent practice that is widely done among the shaivist (tantrics) of India.
The lingam implies much more than seems obvious and far more than can be put into words. It was realize by sages in deep states of meditation. You can use it as a method for reaching the same state and experience.