Ok, here's a shameless plug for a FANTASTIC book. It's Aaron Shepard's The Business of Writing For Children book.
This book is vital to any author contemplating writing a children's book. It speaks the blunt truth...the writing part is only a tiny piece of the pie. It's also a business and a very difficult one, to put it mildly.
When you buy it, read it from beginning to end. It's an easy read, about 100 pages, and a nice, large font.
Aaron Shepard also has a fantastic web site for authors, please take time to visit it here. I've been reading a lot lately, trying to develop my writing style, and I know a great book when I read one. This is a great book.