The new Internet Explorer 9 beta 1 reportedly is faster, more secure, more standard, and all-around better than IE8. It is Microsoft's attempt to regain market share as Chrome, Firefox and Opera have been gaining more and more users over the past few years. At one time, Microsoft's browser had a market share of over 90% of the Windows web browsers in use but that has recently slipped to about 60%. Taken together, Firefox, Safari, Chrome, and all the other non-Microsoft browsers command about 40% of the market.
The new version 9 presents a simpler user interface. In this case, I would suggest that simpler is better. The goal is to make the browser itself as slimline and discreet as practical. Internet Explorer 9 reportedly also includes some new reliability and security features.
You can find dozens of web sites that describe the changes in the new version 9. I rather enjoyed reading ars technica's multi-page report at http://arstechnica.com/microsoft/news/2010/09/inside-internet-explorer-9-redmond-gets-back-in-the-game.ars
Internet Explorer version 9 requires Windows Vista or Windows 7. It will not work with Windows XP.
I will insert a disclaimer: running beta software always entails some risk of encountering bugs. That's the primary purpose of a beta test: to ask users to run the software to identify any remaining bugs. However, early reports indicate that very few bugs have been found in this version.You can learn more and also download the new Microsoft Internet Explorer 9 beta 1 at http://www.beautyoftheweb.com/