Because the web is a changing and ever evolving organism, it’s important to build sites that can grow with it and easily ride the current instead of drowning when a new wave approaches.
Clean markup and building with web standards not only helps you do this, but will save you both time and money in the long run.
The compatibility table on QuirksMode have been updated with information on IE8 in both standards mode and Compatibility View mode.
Every web developer today faces the challenge of checking website compatibility across a large pool of browsers and browser versions in the marketplace. Up and until now, either you could install every browser, verify the website via a visual inspection and debug with tools specialized to that browser, or you could send a URL to a third-party screenshotting service like BrowserShots for an all-in-one visual inspection. The former is messy and tedious but gives you more control and an opportunity to diagnose problems, whilst the latter is simple but slow and useless to fix the problem. Needless to say, SuperPreview is the best of both worlds.
http://www.istartedsomething.com/20090318/expression-web-superpreview-cross-browser-testing/