A friend of mine is getting a submission package ready for an agent, and it occurs to me that I should share the book recommendation I gave her to everyone:
YOUR NOVEL PROPOSAL: From Creation to Contract by Blythe Camenson and Marshall J. Cook.
Every time I sit down to write a proposal I review this book's chapter six: synopses (which, since much of the other information gets out-of-date quickly, is worth the price of the book). The book gives sample synopses, talks about what needs to be in a synopses, what it's used for, and how to format a synopsis. It's really awesome. It seems to be out of print, but I had no trouble getting a used copy a few years ago when I thought I lost my original.
I liked this book so much, I bought it twice! :-)