The I Ching, or "Book of Changes," was specifically written to be a divination manual, a book of power. Ancient soothsayers used it to predict the outcome of their patrons' plans. The classic commentators, however, reinterpreted the Changes in moral and metaphysical terms, making it an ancient Asian system of divination and understanding the cosmos and one's relationship to it.
Legend has it that the I Ching was invented by Chinese Emperor Fu-hsi around 2852 B.C.E. It is composed of 64 different hexagrams, with each hexagram containing a six-line figure. Each of these symbolizes a different human situation, and each of a hexagram's six lines symbolizes a different stage or aspect of that situation, evolving forward in time and upward in society from the bottom of the hexagram to the top. There are 4,096 answers that are possible with this combination.
The symbolism of the Changes is based on seeing solid lines as strong and active, and broken lines as weak and acquiescent. The meanings of all the hexagrams are ultimately derived from this simple symbolism. Each hexagram can be analyzed into an upper group of three lines and a lower group of three lines. These are called the upper and lower "trigrams." There are eight different trigrams and each of them has a specific symbolic meaning based on its arrangement of solid and broken lines. For example, a weak line under two solid lines makes the trigram "Kneel in Submission." The meanings of the hexagrams are related to those of the trigrams that make them up. For example, the hexagram "Subjugated" consists of the trigram Kneel in Submission under the trigram Strong Action, which is made up of three solid lines.
The I Ching is read by throwing yarrow stalks or coins, with coins being the much simpler and more accessible method. It can be consulted with three pennies, although special Chinese coins can be used if you can find access to them.
There are two different types of lines in the I Ching -- the yin line and the yang line. The yin relates to the feminine and the receptive, while the yang is the masculine and active (yes, these attributes are a bit sexist, but this is an ancient system. You can ignore "masculine" and "feminine" altogether if you choose). The yin line appears as a broken line, while the yang line is unbroken.
When tossing the coins, first decide which side of the coin represents which type of line; I usually use heads for yang, tails for yin, which is most common. A numerical value is given to each side of the coin, thus heads equals the value of 3, and tails the value of 2. You throw the three coins six times, writing down the appropriate line each time, going from bottom to top. The types of lines possible are as follows:
___x___ 6 (moving) three tails
_______ 7 (young yang) two tails, one head
___ ___ 8 (young yin) two heads, one tail
___0___ 9 (moving) three heads
Once you have thrown the coins six times, you will have a hexagram composed of the upper trigram (the top three lines), and the lower trigram (the bottom three lines). Consult the I Ching book of your choice, finding the hexagram you have thrown, and read the interpretation.
The I Ching is part of a holistic spiritual system, and should not be taken lightly. Many Westerners find it difficult to use as an oracle, yet many others find it immensely accurate and extraordinarily helpful in terms of understanding.
~from Maat's Book of Shadows
A free I Ching reading can be found here: http://www.facade.com/iching/
An excellent resource for the I Ching on the 'Net is here: http://pacificcoast.net/~wh/Index.html