The default IIS Express configuration allows users to run websites without administrative privileges. The setup program also installs a self-signed server certificate that enables standard users to run a site over SSL.
Certain tasks do require elevated user rights. They include:
Running a website on port 80 or another reserved port
Installing a custom SSL certificate
Running network-facing websites
You must also have administrator user rights when using IIS Express on Windows Server 2003 SP2+.