I wanted to go with option 3, which is a bit more work but I feel the best overall solution. Unfortunately, most of the information and “How To” posts I found out on the internet didn’t work, were horribly outdated or just didn’t make sense. So with that in mind I download the latest version of Ionic’s open source Isapi Rewrite module, read through their documentation and then worked out a configuration in IIS 6 that got everything working. Here is a step by step process that you can follow to easily (and freely) get ASP.NET MVC pretty URLs running under IIS 6 using Ionic’s Isapi Rewrite module.
Read the full post: http://www.schnieds.com/2010/01/using-ionics-isapi-rewrite-for-aspnet.html