I have been working on migrating one of my WordPress sites to a .NET CMS called Orchard. WordPress is great for blogging, but when it comes to extending the functionality, i much rather work with a .NET based CMS then WordPress. Orchard CMS is based on ASP.NET MVC3, Razor, NHibernate and a lot of other .NET goodies.
I was surprised to find that there was no import from WordPress import functionality in Orchard, so I created a module that will read the wordpress export xml and create blog posts in Orchard. The module can be found on GitHub:
https://github.com/moberg/WordpressImport
To use it, first create an export file from WordPress:

Then browse WordPress Import in the OrchardAdmin interface, select which blog you want to import the posts to and pick the export xml file:

The URLs for the posts will be kept. WordPress categories are converted to tags in Orchard.
Let me know if you run into any issues.