This is required reading before you redesign/renovate your website. You could lose all of your cherished search engine rankings for a significant time or even permanently. Here are a couple sites I’ve found that half already covered the topic.

Oops, I Redesigned My Website! Best Practices for a Website …
27 Jun 2008 … How can I make sure that I don’t lose my search engine rankings? … you’ll be in a good position to manage your site redesign with care. … reports we’ve read say that Google will come back again if a page fails once. … After a redesign be sure to run a link validator on your website to be sure …
www.yourseoplan.com/website–redesign-seo/

Lost Organic rankings after website redesign – Webmaster Central Help
Lost Organic rankings after website redesign. … My company website completely dropped off Google rankings for our target key phrases only. …
www.google.ru/support/forum/p/Webmasters/thread?tid…hl…