HTML Pre-launch Flight Check
AnyBrowser have a lot of tools for you to use when validating and preparing your website for deployment including:
Engine View (See how your site might get listed by search engine spiders.)
Not a bad list, don’t forget that ALL web developers should validate their pages, perform link checking and test on different resolutions before going live.
Another great site for viewing your website on any platform and/or operating system is Browser Cam. I use this one all the time, it’s a paid service but invaluable unless you are in abundance of (X)HHTML/CSS greatness that you don’t need it!