According to the Microsoft engineers this is not possible with IIS 6. However they have added a new feature in IIS 7.5 and ASP.Net 4.0 that has a nice provision for exactly what i'm looking for here. It's called the "preloadProvider". Here is an example snippet below (very cool!).
http://forums.iis.net/p/1158476/1907392.aspx
Because a single application pool can contain multiple applications, you specify individual applications to be automatically started by using the following configuration in theapplicationHost.config file:
<sites>
<site name="MySite" id="1">
<application path="/"
preloadEnabled="true"
preloadProvider="PrewarmMyCache" >
<!-- Additional content -->
</application>
</site>
</sites>
<!-- Additional content -->
<preloadProviders>
<add name="PrewarmMyCache"
type="MyNamespace.CustomInitialization, MyLibrary" />
</preloadProviders>
When an IIS 7.5 server is cold-started or when an individual application pool is recycled, IIS 7.5 uses the information in the applicationHost.config file to determine which Web applications need to be automatically started. For each application that is marked for auto-start, IIS7.5 sends a request to ASP.NET 4.0 to start the application in a state during which the application temporarily does not accept HTTP requests. When it is in this state, ASP.NET instantiates the type defined by the preloadProvider attribute (as shown in the previous example) and calls into its public entry point.
You create a managed auto-start type with the necessary entry point by implementing the IProcessHostPreloadClient interface, as shown in the following example:
public class CustomInitialization : System.Web.Hosting.IProcessHostPreloadClient
{
public void Preload(string[] parameters)
{
// Perform initialization.
}
}
After your initialization code runs in the Preload method and the method returns, the ASP.NET application is ready to process requests.
With the addition of auto-start to IIS 7.5 and ASP.NET 4.0, you now have a well-defined approach for performing expensive application initialization prior to processing the first HTTP request. For example, you can use the new auto-start feature to initialize an application and then signal a load-balancer that the application was initialized and ready to accept HTTP traffic.
I would suggest running perfmon for a 24 hours and see if you can determine what resources are being used. Indeed they might already be running on all cores . . . Also, if their web app is a heavily threaded system, then it will take full advantage of multiple cores(at least ours does). Threads, not worker processes, are what actually count for processor utilization.
Best Answer
I did some research and found this useful article, which cover a number of potential issues, and outlines some pros and cons:
EDIT:
http://blogs.iis.net/chrisad/1342059