Which version of IIS should I choose?
Unless you have specific reasons to use IIS 6, such as a need for FrontPage Extensions, you should choose IIS 7. If you want PHP 5 support, you must choose IIS 7.
IIS 7 is Microsoft's latest version of its Internet Information Services Web server. Its modular architecture provides a platform for the development and deployment of dynamic Web applications and websites. IIS 7 was designed for security, speed and ease of use.
Our hosting accounts running IIS 7 are compatible with ASP.NET runtime 3.5 (and 4.0 with Web Hosting), a development framework that supports numerous Web technologies, including Language Integrated Query (LINQ), Windows Presentation Foundation (WPF), Windows Workflow Foundation (WF), Windows Communication Foundation (WC) and Silverlight. For more information, see .NET Framework.
IIS 7 offers two pipeline modes. Integrated pipeline mode handles all requests through a unified pipeline because of the integration of ASP.NET's runtime with the Web server. IIS 7's classic mode behaves in the same manner as IIS 6, using two pipelines to process requests--one for native-code application components and the other for managed code application components.
Full support for PHP 5 is enabled by default on all accounts running IIS 7. With PHP 5, you can install a variety of quick-install applications and integrate PHP 5 scripts and code into your site. PHP 4 is not supported on IIS 7 accounts.
For more information on Internet Information Services 7, see Microsoft's Internet Information Services 7.0.