Hi,
Tutorial for IIS 7.0 on http://php.iis.net can be used to install PHP on IIS 7.5. You can use WebPI (from http://www.microsoft.com/web) to install and configure as well.
IIS 7.5 has ability to monitor changes to php.ini so that any change will trigger a process pool recycle. This is not covered in the walkthrough. PHP installer also doesn't set monitorChangesTo property. If you want to enable php.ini monitoring, you need to set this property yourself.
Thanks,
Kanwal