Using the IsolateStorageFile class

Has anyone here had any experience with the IsolatedStorageFile class in C#? I am writing a Silverlight app that needs access to the file system to allow the user to load a file into the app (and subsequently save a file on his/her computer), and it seems that going through Isolated Storage is the only way to access the file system in any way, shape, or form using Silverlight.

However I am not very familiar with it, and I was wondering where it actually creates this store on the hard disk? I wrote some code to use the class and write out an XML file, but I don't see it anywhere on disk, so I am wondering if anything happened at all, or if there is any way to verify if anything happened.