If you're thinking about self-publishing, I recommend this site, which is maintained by a company called RJ Communications. More specifically, I recommend their newsletter, Publishing Basics, which you can sign up for by clicking here.
The information is extremely practical. When CP, DC and I first talked about starting the Press, one of the hardest things to find out was how much it would cost to print a book. The pricing I researched was all over the map. But I had been getting the newsletter, and one of the articles (very timely) was basically a matrix showing how much it cost to print a book according to quantities, type of printing (offset versus digital), etc.
Now I work for a magazine that covers the printing industry, and all that information is second nature, but at the time, it was a critical resource, because the printing cost for us is the greatest expense, and we couldn't budget realistically until we knew what it would be.