How to loop through web sites in IIS and change the version of .net and change application pool used?

Have a look at the scripts in this link:

http://stackoverflow.com/questions/20923/vbscript-iis-how-do-i-automatically-set-asp-net-version-for-a-particular-websit

Thanks. That's a start. It doesn't answer two of my issues:
1. How to loop through all of my sites in IIS to apply this
2. How to change the Application Pool at the same time

Well you can script it to loop through you sites I do not know what sites you have or what you want to do to them I presume you will have a list of the sites you want to do. Also do you *really* want to do 3000 sites on mass without testing them?? That sounds crazy. Are ALL of the 100% OK to do this huge change?

You have the method to change the site via a script now and base this on what criteria you desire. I presumed you know how to use adsutil and scripting (as you say you use them) as you manage these large farms.

Here are a load of scripts to help you further if you need to do multiple functions.
http://www.iisfaq.com/Default.aspx?tabid=2538

I don't understand what you mean about changing the application pool?

There are no .NET configuration settings for app pools. Inside the app pool it will run the .net 1.1 and 2.0 code or php or whatever the applications/sites run but there is no config for it.

So the app pools you have for all these that currently run a .net 1.1 app it will still run the same if teh app is .net 2.0 or php. There is nothing to change in the app pool.

Sorry some background may help here:
I am getting errors that I have at least 2 different versions of .Net set within the same application pool.
I gather this means that one or more of the websites we host (which are in fact classic ASP and don't even use .Net) have been set differently. I'd like to make sure they are all set to the same thing.

As an aside, I have a memory leak somewhere and looks like one ore more of my sites is/are the problem and I would like to isolate these by grouping similar sites into different application pools so I can narrow down that problem.

Thanks for your help.