When you create a new web site in IIS 7.5, an Application Pool is created by default with the same name as the web site.
After Windows Server 2008 SP2, you may select “ApplicationPoolIdentity” as the account to run the app pool with.
ApplicationPoolIdentity is an account on the local machine with the same name as the Application Pool.
If you want to give your web application access to files or other resources outside your web root directory, perform these steps:
- Right Click the file or folder (or registry key?) you want to give access to, and select Properties from the dropdown.
- Go to the Security Tab, click the “Edit…” button.
- Click “Add…”.
- Click “Locations…” and select the local machine.
- Under “Enter the object names to select…”, type IIS AppPool\<ApplicationPoolIdentity>, where <ApplicationPoolIdentity> is the same as the Application Pool name.
- Give rights as needed, click OK as many times as it takes, etc.
I think this should be enough to get you started.
Source: http://learn.iis.net/page.aspx/624/application-pool-identities/
