Recently Microsoft has released Internet Explorer 7 to the public. It brings some more compatibility to web standards as its predecessor, IE6, but is definitely more secure.
Now the majority of users surfing the web has installed IE6 on their machines. Many of them won't quickly upgrade to IE7 I'm sure.
As a web designer this brings one big problem to you: testing your website layout/javascript on two different Internet Explorer versions. This isn't so easy, because the installation of IE7 removes the IE6 from your Windows (that's why I was afraid to install IE7).
But there's a really easy solution to this problem that I wasn't aware of before: MultipleIEs. This is a small program that can install each version of the Internet Explorer since IE 3.0 as a separate program onto your machine!
I have only tested it with IE6 so far, but it works as promised! Now I can run IE6 and IE7 on one Windows and test websites against both browser versions.
Just try it - it's free (of course you need Windows)!