Is there a limit to how many sites can be hosted on a single IP address when using HTTP Host Headers on Windows 2008?

From a (now broken) IIS FAQ at TechNet:

Q. Does Web server performance degrade when Web sites use host headers instead of IP addresses?

A. The overhead for IIS to check a host header is negligible compared to the total cost of satisfying an HTTP request, even for a static file. Also, host headers scale better than IP addresses when you host thousands of Web sites on a server.

It doesn't sound like there's a real upper limit to the number of host header sites you can have, but I've yet to find any hard evidence.

Have a look at this link: http://www.it-notebook.org/iis/article/host_headers_vs_ip.htm

It appears to be that using Host Headers is the prefered method.