I for one hate trying to come up with a synopsis or even a blurb, and so Mike Wells's little trick here can help if your book conforms to one of the more common narrative structures. Remember, a synopsis isn't as much a writing exercise as it is a marketing exercise. Those skill sets overlap but aren't the same by a long shot.
If you choose to go the traditional route, agents and editors alike are bombarded with so many queries that if they find themselves having to do much mental work to understand the gist of your book, they will simply pass on to the next one. The same goes for self-publishing--all the retailers and distributors require short descriptions of your book. For example, Smashwords requires a description that can be no more than 400 characters, including spaces! That's short, folks!
Read his suggestion here: http://mikewellsblog.blogspot.com.au/2011/04/secret-formula-for-creating-short.html