One of our contributors, Jaimie Sirovich, has just released a book that deals with this exact problem. The book is called Professional Search Engine Optimization with PHP: A Developer’s Guide to SEO and you can get it pretty much anywhere, including Amazon and B&N.
The book covers topics like content relocation, URL rewriting, duplicate content issues, feeds and social bookmarking, sitemaps and much more. It also goes into areas like Black Hat SEO, covering most popular tactics and providing developers with ideas on how to better prevent comment spam, HTML insertion attacks, etc.
Developers, are you tired of people calling your IT department a “business prevention department”? Do yourself a favor and invest 26 bucks in your career. Business owners and managers, get your developers this book. You could be spending thousands of dollars on the site that is doomed to fail in the SERPs.