I'm not an expert, but I did consult the I Ching yesterday. I don't think websites do the I Ching justice. It's better consulted in book form IMO.
It is an ancient book of Wisdom from China that present insight to situations you are likely to see in life, how the situation changes (it's also known as the book of changes), and what the resolution will be. I feel it helps you think outside of the box or get insight that you might have not considered, etc.
There are various ways to consult the book. You may read about your situation directly should you know what you're facing. Or, you may ask a question and use a variety of methods for generating a hexagram with a number of changing lines. In this last way, you are essentially asking the universe to provide you with divination much like an oracle.
Yesterday I used the six-coin method for consulting. Here 5 coins are similar and one is different. I posed my question while shaking the coins in my hands. Then let them fall on the floor and arranged them in a line according to how they landed. The different coin was used to develop the changing line. This is a simple method that only generates one changing line. Heads represent yang (solid) lines and tails yin (broken) lines.
I have 2 books: The Laws of Change by Balkin is quite controversial but I like it in that it gives a lot of information and discussion. It's the one I read the most. The other is more traditional: The Complete I Ching by Master Huang.
If you have an iPhone there's a decent app called Yi Jing.
Enjoy!