<p>Does any one know the best way to deploy a resource file to the App_GlobalResource folder of the web application when a feature is activated?</p>

Application resource files cannot be deployed via a feature unless you execute some code and start a SharePoint timer job that copies the files to the App_GlobalResources folder on each Web front-end server.
You should instead let the SharePoint solutions framework deploy the .RESX files to the App_GlobalResources folder on each server. You can specify application resource files as follows in the manifest.xml file of your WSP solution package:
```
```
<?xml version="1.0" encoding="utf-8"?>
<Solution SolutionId="{185E973C-3A10-4e2a-9E0F-DC14414551F9}" 
          xmlns="http://schemas.microsoft.com/sharepoint/" 
          DeploymentServerType="WebFrontEnd">

  <ApplicationResourceFiles>
    <ApplicationResourceFile Location="yourappname.resx"/>
    <ApplicationResourceFile Location="yourappname.en-US.resx"/>
  </ApplicationResourceFiles>

 ...
</Solution>
```
```
When you deploy the WSP solution package using STSADM or Central Administration, the SharePoint solutions framework will start a timer job that deploys these files to the App_GlobalResources folder of all the Web applications you decided to deploy the solution to.