How to download IIS?
From:http://blogs.iis.net/davcox/archive/2009/06/29/how-to-download-iis.aspx
A lot of folks ask us how to "download" IIS; since other web server offerings are available for download on a multiple of platforms, it's an obvious question for the Microsoft web platform stack as well. The answer "for now" is that you can't download IIS because it only comes with Windows.
Well, IIS has historically shipped as part of each operating system, and we have never back-ported IIS from one OS to another. The exception being that we have ported certain features back in our Out of Band modules (extensions) as we like to call them.
Now that we have shipped Web Application Gallery, you can install IIS easily through that tool.
So let's break it down by IIS version and operating system. Plus I have some comments on my experience with these versions: IIS 4.0 - NT 4.0, Option Pack 4
I remember when I was a teaching assistant at WWU in Bellingham, WA, we were using IIS 3.0; and then I read that IIS 4.0 came out; after talking my professor into it, I installed it and wow, the stability went way up! Now I didn't need to reboot the server before>IIS 5.0 - Windows 2000 (Professional & Server SKU's) (use Add/Remove programs -> Windows Components)
When I joined Microsoft, I was part of a team busy doing a re-architecture of IIS (the genesis of the IIS 6 project) while another team finished up IIS 5 and shipped it. This>IIS 5.1 - Windows XP (same as IIS 5 - use Add/Remove programs -> Windows Components)
I remember being frustrated that we had to ship IIS 5.1 (basically a big bug fix>IIS 6.0 - Windows Server 2003
IIS6 was a great>IIS 7.0 - Windows Vista SP1& Windows Server 2008 (UI)or Windows Server 2008 (command line)
IIS7 was a big change in terms of setup complexity, configuration, and UI. All three of these changed drastically to allow for complete customizability and extensibility of the web platform. Now you can add your own components to IIS and get full-featured management support in terms of integration with our configuration and most of our administration tool such as appcmd and our new UI. IIS 7.5 - Windows 7 - coming soon!!!
IIS7.5 is a minor>IIS 8.0 - ??? - it willl blow your mind! :)