1. In a local computer system that has a file system and communicates with a remote computer system, a method of backing up selected files associated with the file system, comprising the acts of: receiving user input specifying one or more files to be backed up from among a plurality of files associated with the file system of the local computer system; using a mirroring driver that is associated with a file system driver of the local computer system, intercepting write requests that have been transmitted by an application operating at the local computer system to the file system driver; for each of the intercepted write requests: determining, by the mirroring driver, whether the intercepted write request is associated with one of the specified one or more files; and if it is determined that the intercepted write request is associated with said one of the specified one or more files, transmitting the intercepted write request to the remote computer system such that the remote computer system can execute the intercepted write request on a backup copy of said one of the specified one or more files.