The thing about Karl Barth is that it's really important for Christians to read him, but it's pretty tough to know how to start. The best advice is just to start. Apart from that, however, thankfully there's an increasing collection of online resources that can help. Here are links to some of both the recently discovered and the more enduring variety.
This weekend over at Die Evangelischen Theologen, W. Travis McMaken's theo-blog round-up included two that I hadn't seen before:
First, for an excellent video introduction to Barth (which you can watch in less than half an hour), check this one out, made by St. John's Nottingham and narrated by Aberdeen's Tom Greggs:
Second, at Canon and Creed, Matthew Wilcoxen (a PhD candidate at Charles Stuart University in Sydney, Australia) has begun blogging a Church Dogmatics Paraphrase--which might be just the thing for those that want to delve into the thing but have need of an entry point. If you are going to try to get to know this masterpiece of modern theology, you might as well begin at paragraph one.
Beyond these recent discoveries, of course, there are also a few theo-blog "classics" worth checking out:
If you are looking for a primer on "how to start reading Karl Barth" you still can't do much better than this one by the aforementioned Travis or this one by Darren Sumner at Theology Out of Bounds.
And last but not least, if you are looking for something even shorter than a paraphrase, there is always Ben Myers' impressive single-sentence encapsulation of each part-volume of the Church Dogmatics, over at Faith and Theology, which you can access here.