The prerequisites for running WordPress are PHP and MySQL, which are actually quite easy to set up. However, if you're using Vista, you won't be able to install Apache because it will throw an error (this issue is unrelated to IIS7 occupying port 80). Therefore, you have to use IIS7.
In this article, you will learn:
1. How to install IIS7 on Vista and run PHP
2. How to run WordPress on Vista