I always wanted to and just recently started tentatively studying the Changes. Not so much as a system of divination but as an overarching cosmogony of much of chinese thought.
It is not exactly an easy endeavour, not only because of the cryptic nature of the book and symbology, but also because of all the historical cruft that it has accumulated. It is often linked to daoism, but daoism itself has grown way beyond it's initial shape.
For example, the notions of yin and yang, so seemingly central to both systems, has but very minor representation in the original works, in the Zhouyi there is but a couple of lines with explicit mention, the daodejing iirc has none, and Zhuangzi too mentions them only in passing.
Later scholars from many schools took from the yijing, and it can be shown in both confucian and later daoist traditions. Confucius himself is credited the Great Commentary, the notions of the trigrams themselves seem to have been, too, developed well after the Zhouyi was written. They are actually the ones that bridge the rather archaic zhouyi to the whole yingyang system.
The received yijing that chinese know today actually come with a great deal of additional text, also known as the Ten Wings, which are several layers of commentary added over the ages. But the core essence (ie, the Zhouyi) is merely the hexagrams and the comments on the lines.
Interesting is the daoist school that built a system of alchemy and magic on top of the original symbolism of the changes, but also the neoconfucian school which also makes up a big coherent model of the universe based on much the same principles. I don't know very well to what extent these two traditions overlap, and both seem to have influenced traditional chinese medicine as well.
As of right now, besides studying the Zhouyi itself, I've been looking at the Illustrated Canon of Chen Family Taijiquan, where these systems of thought all seem to converge to a certain extent. Indeed, taijiquan is quite recent, considering the lifetime of the changes.
But therein lies the difficulty, for the system expounded in the Chen family canon necessarily draws on many sources and a long tradition, and the exact origins and dates thereof of these ideas is hard to trace, whereas the original texts of both the dao as well as the yijing itself have but a very minimal language. Especially the dPost too long. Click here to view the full text.